198630a809
reason: We can reduce a function call to improve performance. Signed-off-by: hujun5 <hujun5@xiaomi.com>
474 lines
12 KiB
C
474 lines
12 KiB
C
/****************************************************************************
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* fs/shm/shmfs.c
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <assert.h>
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#include <nuttx/fs/ioctl.h>
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#include <nuttx/mm/map.h>
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#if defined (CONFIG_BUILD_KERNEL)
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#include <nuttx/arch.h>
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#include <nuttx/pgalloc.h>
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#include <nuttx/sched.h>
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#endif
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#include "shm/shmfs.h"
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#include "inode/inode.h"
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#include "sched/sched.h"
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/****************************************************************************
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* Private Function Prototypes
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****************************************************************************/
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static int shmfs_close(FAR struct file *filep);
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static ssize_t shmfs_read(FAR struct file *filep, FAR char *buffer,
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size_t buflen);
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static ssize_t shmfs_write(FAR struct file *filep, FAR const char *buffer,
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size_t buflen);
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static int shmfs_truncate(FAR struct file *filep, off_t length);
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#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
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static int shmfs_unlink(FAR struct inode *inode);
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#endif
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static int shmfs_mmap(FAR struct file *filep,
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FAR struct mm_map_entry_s *entry);
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static int shmfs_munmap(FAR struct task_group_s *group,
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FAR struct mm_map_entry_s *entry,
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FAR void *start,
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size_t length);
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/****************************************************************************
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* Public Data
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****************************************************************************/
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const struct file_operations g_shmfs_operations =
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{
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NULL, /* open */
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shmfs_close, /* close */
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shmfs_read, /* read */
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shmfs_write, /* write */
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NULL, /* seek */
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NULL, /* ioctl */
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shmfs_mmap, /* mmap */
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shmfs_truncate, /* truncate */
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NULL, /* poll */
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#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
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shmfs_unlink /* unlink */
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#endif
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};
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Name: shmfs_read
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****************************************************************************/
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static ssize_t shmfs_read(FAR struct file *filep, FAR char *buffer,
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size_t buflen)
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{
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FAR struct shmfs_object_s *sho;
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ssize_t nread;
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off_t startpos;
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off_t endpos;
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DEBUGASSERT(filep->f_inode->i_private != NULL);
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sho = filep->f_inode->i_private;
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if (filep->f_pos > sho->length)
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{
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return 0;
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}
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/* Handle attempts to read beyond the end of the file. */
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startpos = filep->f_pos;
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nread = buflen;
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endpos = startpos + buflen;
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if (endpos > sho->length)
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{
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endpos = sho->length;
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nread = endpos - startpos;
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}
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/* Copy data from the memory object to the user buffer */
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if (sho->paddr != NULL)
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{
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memcpy(buffer, (FAR char *)sho->paddr + startpos, nread);
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filep->f_pos += nread;
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}
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else
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{
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DEBUGASSERT(sho->length == 0 && nread == 0);
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}
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return nread;
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}
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/****************************************************************************
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* Name: shmfs_write
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****************************************************************************/
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static ssize_t shmfs_write(FAR struct file *filep, FAR const char *buffer,
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size_t buflen)
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{
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FAR struct shmfs_object_s *sho;
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ssize_t nwritten;
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off_t startpos;
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off_t endpos;
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DEBUGASSERT(filep->f_inode->i_private != NULL);
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sho = filep->f_inode->i_private;
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/* Handle attempts to write beyond the end of the file */
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startpos = filep->f_pos;
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nwritten = buflen;
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endpos = startpos + buflen;
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/* Desn't support shm auto expand, truncate first */
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if (endpos > sho->length)
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{
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return -EFBIG;
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}
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/* Copy data from the user buffer to the memory object */
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if (sho->paddr != NULL)
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{
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memcpy((FAR char *)sho->paddr + startpos, buffer, nwritten);
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filep->f_pos += nwritten;
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}
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else
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{
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DEBUGASSERT(sho->length == 0 && nwritten == 0);
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}
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return nwritten;
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}
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/****************************************************************************
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* Name: shmfs_release
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****************************************************************************/
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static int shmfs_release(FAR struct inode *inode)
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{
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/* If the file has been unlinked previously, delete the contents.
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* The inode is released after this call, hence checking if i_crefs <= 1.
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*/
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int ret = inode_lock();
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if (ret >= 0)
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{
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if (inode->i_parent == NULL &&
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inode->i_crefs <= 1)
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{
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shmfs_free_object(inode->i_private);
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inode->i_private = NULL;
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ret = OK;
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}
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inode_unlock();
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}
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return ret;
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}
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/****************************************************************************
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* Name: shmfs_close
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****************************************************************************/
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static int shmfs_close(FAR struct file *filep)
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{
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/* Release the shmfs object. The object gets deleted if no-one has
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* reference to it (either mmap or open file) and the object has been
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* unlinked
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*/
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return shmfs_release(filep->f_inode);
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}
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/****************************************************************************
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* Name: shmfs_truncate
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****************************************************************************/
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static int shmfs_truncate(FAR struct file *filep, off_t length)
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{
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FAR struct shmfs_object_s *object;
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int ret;
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if (length == 0)
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{
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return -EINVAL;
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}
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ret = inode_lock();
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if (ret >= 0)
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{
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object = filep->f_inode->i_private;
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if (!object)
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{
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filep->f_inode->i_private = shmfs_alloc_object(length);
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if (!filep->f_inode->i_private)
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{
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filep->f_inode->i_size = 0;
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ret = -EFAULT;
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}
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else
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{
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filep->f_inode->i_size = length;
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}
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}
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else if (object->length != length)
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{
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/* This doesn't support resize */
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ret = -EINVAL;
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}
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inode_unlock();
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}
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return ret;
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}
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/****************************************************************************
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* Name: shmfs_unlink
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****************************************************************************/
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#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
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static int shmfs_unlink(FAR struct inode *inode)
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{
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int ret = inode_lock();
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if (ret >= 0)
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{
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if (inode->i_crefs <= 1)
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{
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shmfs_free_object(inode->i_private);
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inode->i_private = NULL;
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}
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inode_unlock();
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}
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return ret;
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}
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#endif
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/****************************************************************************
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* Name: shmfs_map_object
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****************************************************************************/
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static int shmfs_map_object(FAR struct shmfs_object_s *object,
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FAR void **vaddr)
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{
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int ret = OK;
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#ifdef CONFIG_BUILD_KERNEL
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/* Map the physical pages of the shm object with MMU. */
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FAR struct tcb_s *tcb = this_task();
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FAR struct task_group_s *group = tcb->group;
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FAR uintptr_t *pages = (FAR uintptr_t *)&object->paddr;
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uintptr_t mapaddr;
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unsigned int npages;
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/* Find a free vaddr space that satisfies length */
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mapaddr = (uintptr_t)vm_alloc_region(get_group_mm(group), 0,
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object->length);
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if (mapaddr == 0)
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{
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return -ENOMEM;
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}
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/* Convert the region size to pages */
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npages = MM_NPAGES(object->length);
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/* Map the memory to user virtual address space */
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ret = up_shmat(pages, npages, mapaddr);
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if (ret < 0)
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{
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vm_release_region(get_group_mm(group), (FAR void *)mapaddr,
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object->length);
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}
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else
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{
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*vaddr = (FAR void *)mapaddr;
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}
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#else
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/* Use the physical address directly */
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*vaddr = object->paddr;
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#endif
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return ret;
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}
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/****************************************************************************
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* Name: shmfs_add_map
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****************************************************************************/
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static int shmfs_add_map(FAR struct mm_map_entry_s *entry,
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FAR struct inode *inode)
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{
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entry->munmap = shmfs_munmap;
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entry->priv.p = (FAR void *)inode;
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return mm_map_add(get_current_mm(), entry);
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}
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/****************************************************************************
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* Name: shmfs_mmap
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****************************************************************************/
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static int shmfs_mmap(FAR struct file *filep,
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FAR struct mm_map_entry_s *entry)
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{
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FAR struct shmfs_object_s *object;
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int ret = -EINVAL;
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/* We don't support offset at the moment, just mapping the whole object
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* object is NULL if it hasn't been truncated yet
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*/
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if (entry->offset != 0)
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{
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return ret;
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}
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/* Keep the inode when mmapped, increase refcount */
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ret = inode_addref(filep->f_inode);
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if (ret >= 0)
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{
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object = filep->f_inode->i_private;
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if (object)
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{
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ret = shmfs_map_object(object, &entry->vaddr);
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}
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else
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{
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ret = -EINVAL;
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}
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if (ret < 0 ||
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(ret = shmfs_add_map(entry, filep->f_inode)) < 0)
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{
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inode_release(filep->f_inode);
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}
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}
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return ret;
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}
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/****************************************************************************
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* Name: shmfs_unmap_object
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****************************************************************************/
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static int shmfs_unmap_area(FAR struct task_group_s *group,
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FAR void *vaddr, size_t length)
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{
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int ret = OK;
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#ifdef CONFIG_BUILD_KERNEL
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unsigned int npages;
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/* Convert the region size to pages */
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if (group)
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{
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npages = MM_NPAGES(length);
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/* Unmap the memory from user virtual address space */
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ret = up_shmdt((uintptr_t)vaddr, npages);
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/* Add the virtual memory back to the shared memory pool */
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vm_release_region(get_group_mm(group), vaddr, length);
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}
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#endif
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return ret;
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}
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/****************************************************************************
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* Name: shmfs_munmap
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****************************************************************************/
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static int shmfs_munmap(FAR struct task_group_s *group,
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FAR struct mm_map_entry_s *entry,
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FAR void *start,
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size_t length)
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{
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FAR struct inode *inode;
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int ret;
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/* Partial unmap is not supported yet */
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if (start != entry->vaddr || length != entry->length)
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{
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return -EINVAL;
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}
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inode = (FAR struct inode *)entry->priv.p;
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/* Unmap the virtual memory area from the user's address space */
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ret = shmfs_unmap_area(group, entry->vaddr, entry->length);
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/* Release the shmfs object. The object gets deleted if no-one has
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* reference to it (either mmap or open file) and the object has been
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* unlinked
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*/
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if (ret == OK)
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{
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ret = shmfs_release(inode);
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}
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/* Unkeep the inode when unmapped, decrease refcount */
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if (ret == OK)
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{
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inode_release(inode);
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/* Remove the mapping. */
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ret = mm_map_remove(get_group_mm(group), entry);
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}
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return ret;
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}
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