Summary:
1.Modified the i_crefs from int16_t to atomic_int
2.Modified the i_crefs add, delete, read, and initialize interfaces to atomic operations
The purpose of this change is to avoid deadlock in cross-core scenarios, where A Core blocks B Core’s request for a write operation to A Core when A Core requests a read operation to B Core.
Signed-off-by: chenrun1 <chenrun1@xiaomi.com>
pointer comparison is unsigned, when returning -errno will be converted
to a large positive number, can not enter the error handling branch,
therefore, the error code is returned directly and the sem is returned
through the parameters.
Signed-off-by: zhanghongyu <zhanghongyu@xiaomi.com>
Follow the POSIX specification in https://pubs.opengroup.org/onlinepubs/9699919799/functions/sem_open.html, update the logic for condition that the semaphore name length is greater than PATH_MAX or a component length is greater than NAME_MAX.
Signed-off-by: yangjiao <yangjiao@xiaomi.com>
Note: all attributes is guarded by PSEUDOFS_ATTRIBUTES to save the space
Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
Change-Id: I664d60382e356068fd920f08aca5b4a49d8d92a9
Resolution of Issue 619 will require multiple steps, this part of the first step in that resolution: Every call to nxsem_wait_uninterruptible() must handle the return value from nxsem_wait_uninterruptible properly. This commit is only for those files under fs/inode. Utility functions under fs/incode were modified so the changes do extend to other fs/ sub-directories as well.
This commit backs out most of commit b4747286b1. That change was added because sem_wait() would sometimes cause cancellation points inappropriated. But with these recent changes, nxsem_wait() is used instead and it is not a cancellation point.
In the OS, all calls to sem_wait() changed to nxsem_wait(). nxsem_wait() does not return errors via errno so each place where nxsem_wait() is now called must not examine the errno variable.
In all OS functions (not libraries), change sem_wait() to nxsem_wait(). This will prevent the OS from creating bogus cancellation points and from modifying the per-task errno variable.
sched/semaphore: Add the function nxsem_wait(). This is a new internal OS interface. It is functionally equivalent to sem_wait() except that (1) it is not a cancellation point, and (2) it does not set the per-thread errno value on return.
libc/semaphore: Add nxsem_getvalue() which is identical to sem_getvalue() except that it never modifies the errno variable. Changed all references to sem_getvalue in the OS to nxsem_getvalue().
sched/semaphore: Rename all internal private functions from sem_xyz to nxsem_xyz. The sem_ prefix is (will be) reserved only for the application semaphore interfaces.
libc/semaphore: Add nxsem_init() which is identical to sem_init() except that it never modifies the errno variable. Changed all references to sem_init in the OS to nxsem_init().
sched/semaphore: Rename sem_tickwait() to nxsem_tickwait() so that it is clear this is an internal OS function.
sched/semaphoate: Rename sem_reset() to nxsem_reset() so that it is clear this is an internal OS function.
