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Fix confusion between byte and block transfers

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git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@2235 42af7a65-404d-4744-a932-0658087f49c3
This commit is contained in:
patacongo 2009-11-06 13:43:21 +00:00
parent bf7555cc4a
commit d9413c1214
2 changed files with 122 additions and 94 deletions
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183
drivers/rwbuffer.c
View File

@ -111,16 +111,16 @@ static void rwb_semtake(sem_t *sem)
* Name: rwb_overlap
****************************************************************************/
static inline boolean rwb_overlap(off_t bufferstart1, size_t buffersize1,
off_t bufferstart2, size_t buffersize2)
static inline boolean rwb_overlap(off_t blockstart1, size_t nblocks1,
off_t blockstart2, size_t nblocks2)
{
off_t bufferend1 = bufferstart1 + buffersize1;
off_t bufferend2 = bufferstart2 + buffersize2;
off_t blockend1 = blockstart1 + nblocks1;
off_t blockend2 = blockstart2 + nblocks2;
/* If the buffer 1 is wholly outside of buffer 2, return false */
if ((bufferend1 < bufferstart2) || /* Wholly "below" */
(bufferstart1 > bufferend2)) /* Wholly "above" */
if ((blockend1 < blockstart2) || /* Wholly "below" */
(blockstart1 > blockend2)) /* Wholly "above" */
{
return FALSE;
}
@ -139,7 +139,7 @@ static inline void rwb_resetwrbuffer(struct rwbuffer_s *rwb)
{
/* We assume that the caller holds the wrsem */
rwb->wrnbytes = 0;
rwb->wrnblocks = 0;
rwb->wrblockstart = (off_t)-1;
rwb->wrexpectedblock = (off_t)-1;
}
@ -154,17 +154,17 @@ static void rwb_wrflush(struct rwbuffer_s *rwb)
{
int ret;
fvdbg("Timeout!");
fvdbg("Timeout!\n");
rwb_semtake(&rwb->wrsem);
if (rwb->wrnbytes)
if (rwb->wrnblocks)
{
fvdbg("Flushing: blockstart=0x%08lx nbytes=%d from buffer=%p",
(long)rwb->wrblockstart, (long)rwb->wrnbytes, (long)rwb->wrbuffer);
fvdbg("Flushing: blockstart=0x%08lx nblocks=%d from buffer=%p\n",
(long)rwb->wrblockstart, rwb->wrnblocks, rwb->wrbuffer);
/* Flush cache */
ret = rwb->wrflush(rwb->dev, rwb->wrbuffer, rwb->wrblockstart, rwb->wrnbytes);
ret = rwb->wrflush(rwb->dev, rwb->wrbuffer, rwb->wrblockstart, rwb->wrnblocks);
if (ret < 0)
{
fdbg("ERROR: Error flushing write buffer: %d\n", -ret);
@ -225,7 +225,7 @@ static inline void rwb_wrcanceltimeout(struct rwbuffer_s *rwb)
#ifdef CONFIG_FS_WRITEBUFFER
static ssize_t rwb_writebuffer(FAR struct rwbuffer_s *rwb,
off_t startblock, uint32 nbytes,
off_t startblock, uint32 nblocks,
FAR const ubyte *wrbuffer)
{
int ret;
@ -234,17 +234,20 @@ static ssize_t rwb_writebuffer(FAR struct rwbuffer_s *rwb,
rwb_wrcanceltimeout(rwb);
/* First: Should we flush out our cache? */
/* First: Should we flush out our cache? We would do that if (1) we already
* buffering blocks and the next block writing is not in the same sequence,
* or (2) the number of blocks would exceed our allocated buffer capacity
*/
if (((startblock != rwb->wrexpectedblock) && (rwb->wrnbytes)) ||
((rwb->wrnbytes + nbytes) > rwb->wrallocsize))
if (((startblock != rwb->wrexpectedblock) && (rwb->wrnblocks)) ||
((rwb->wrnblocks + nblocks) > rwb->wrmaxblocks))
{
fvdbg("writebuffer miss, expected: 0x%08x, given: 0x%08x",
rwb->wrexpectedblock, startblock);
fvdbg("writebuffer miss, expected: %08x, given: %08x\n",
rwb->wrexpectedblock, startblock);
/* Flush cache */
/* Flush the write buffer */
ret = rwb->wrflush(rwb, rwb->wrbuffer, rwb->wrblockstart, rwb->wrnbytes);
ret = rwb->wrflush(rwb, rwb->wrbuffer, rwb->wrblockstart, rwb->wrnblocks);
if (ret < 0)
{
fdbg("ERROR: Error writing multiple from cache: %d\n", -ret);
@ -254,24 +257,26 @@ static ssize_t rwb_writebuffer(FAR struct rwbuffer_s *rwb,
rwb_resetwrbuffer(rwb);
}
/* writebuffer is clear? Then initialize it */
/* writebuffer is empty? Then initialize it */
if (!rwb->wrnbytes)
if (!rwb->wrnblocks)
{
fvdbg("Fresh cache starting at block: 0x%08x",startblock);
fvdbg("Fresh cache starting at block: 0x%08x\n", startblock);
rwb->wrblockstart = startblock;
}
/* Add data to cache */
fvdbg("writebuffer: copying from 0x%p to 0x%p",
wrbuffer, &rwb->wrbuffer[rwb->wrnbytes]);
memcpy(&rwb->wrbuffer[rwb->wrnbytes], wrbuffer, nbytes);
fvdbg("writebuffer: copying %d bytes from %p to %p\n",
nblocks * wrb->blocksize, wrbuffer,
&rwb->wrbuffer[rwb->wrnblocks * rwb->blocksize]);
memcpy(&rwb->wrbuffer[rwb->wrnblocks * rwb->blocksize],
wrbuffer, nblocks * rwb->blocksize);
rwb->wrnbytes += nbytes;
rwb->wrexpectedblock = rwb->wrblockstart + rwb->wrnbytes;
rwb->wrnblocks += nblocks;
rwb->wrexpectedblock = rwb->wrblockstart + rwb->wrnblocks;
rwb_wrstarttimeout(rwb);
return nbytes;
return nblocks;
}
#endif
@ -284,7 +289,7 @@ static inline void rwb_resetrhbuffer(struct rwbuffer_s *rwb)
{
/* We assume that the caller holds the readAheadBufferSemphore */
rwb->rhnbytes = 0;
rwb->rhnblocks = 0;
rwb->rhblockstart = (off_t)-1;
}
#endif
@ -305,21 +310,21 @@ rwb_bufferread(struct rwbuffer_s *rwb, off_t startblock,
/* Convert the units from blocks to bytes */
uint32 dwStartBlockOffset = startblock - rwb->rhblockstart;
uint32 dwStartByteOffset = rwb->blocksize * dwStartBlockOffset;
uint32 dwByteCount = rwb->blocksize * nblocks;
off_t blockoffset = startblock - rwb->rhblockstart;
off_t byteoffset = rwb->blocksize * blockoffset;
size_t nbytes = rwb->blocksize * nblocks;
/* Get the byte address in the read-ahead buffer */
ubyte *pchBuffer = rwb->rhbuffer + dwStartByteOffset;
ubyte *rhbuffer = rwb->rhbuffer + byteoffset;
/* Copy the data from the read-ahead buffer into the IO buffer */
memcpy(*rdbuffer, pchBuffer, dwByteCount);
memcpy(*rdbuffer, rhbuffer, nbytes);
/* Update the caller's copy for the next address */
*rdbuffer += dwByteCount;
*rdbuffer += nbytes;
}
#endif
@ -330,12 +335,13 @@ rwb_bufferread(struct rwbuffer_s *rwb, off_t startblock,
#ifdef CONFIG_FS_READAHEAD
static int rwb_rhreload(struct rwbuffer_s *rwb, off_t startblock)
{
/* Get the maximum number of blocks that will fit in the read-ahead buffer */
/* Get the block number +1 of the last block that will fit in the
* read-ahead buffer
*/
size_t maxblocks = rwb->rhallocsize / rwb->blocksize;
off_t endblock = startblock + maxblocks;
off_t endblock = startblock + rwb->rhmaxblocks;
size_t nblocks;
int ret;
int ret;
/* Reset the read buffer */
@ -356,7 +362,7 @@ static int rwb_rhreload(struct rwbuffer_s *rwb, off_t startblock)
{
/* Update information about what is in the read-ahead buffer */
rwb->rhnbytes = nblocks;
rwb->rhnblocks = nblocks;
rwb->rhblockstart = startblock;
}
return ret;
@ -372,6 +378,8 @@ static int rwb_rhreload(struct rwbuffer_s *rwb, off_t startblock)
int rwb_initialize(FAR struct rwbuffer_s *rwb)
{
uint32 allocsize;
/* Sanity checking */
DEBUGASSERT(rwb != NULL);
@ -382,18 +390,16 @@ int rwb_initialize(FAR struct rwbuffer_s *rwb)
/* Setup so that rwb_uninitialize can handle a failure */
#ifdef CONFIG_FS_WRITEBUFFER
DEBUGASSERT(rwb->wrblocks > 0);
DEBUGASSERT(rwb->wrflush!= NULL);
rwb->wrbuffer = NULL;
#endif
#ifdef CONFIG_FS_READAHEAD
DEBUGASSERT(rwb->rhblocks > 0);
DEBUGASSERT(rwb->rhreload != NULL);
rwb->rhbuffer = NULL;
#endif
#ifdef CONFIG_FS_WRITEBUFFER
fvdbg("Initialize the write buffer");
fvdbg("Initialize the write buffer\n");
/* Initialize the write buffer access semaphore */
@ -405,19 +411,23 @@ int rwb_initialize(FAR struct rwbuffer_s *rwb)
/* Allocate the write buffer */
rwb->wrallocsize = rwb->wrblocks * rwb->blocksize;
rwb->wrbuffer = malloc(rwb->wrallocsize);
if (!rwb->wrbuffer)
rwb->wrbuffer = NULL;
if (rwb->wrmaxblocks > 0)
{
fdbg("Write buffer malloc(%ld) failed\n", (long)rwb->wrallocsize);
return -ENOMEM;
allocsize = rwb->wrmaxblocks * rwb->blocksize;
rwb->wrbuffer = malloc(allocsize);
if (!rwb->wrbuffer)
{
fdbg("Write buffer malloc(%d) failed\n", allocsizee);
return -ENOMEM;
}
}
fvdbg("Write buffer size: %d bytes\n", rwb->wrallocsize);
fvdbg("Write buffer size: %d bytes\n", allocsize);
#endif /* CONFIG_FS_WRITEBUFFER */
#ifdef CONFIG_FS_READAHEAD
fvdbg("Initialize the read-ahead buffer");
fvdbg("Initialize the read-ahead buffer\n");
/* Initialize the read-ahead buffer access semaphore */
@ -429,15 +439,19 @@ int rwb_initialize(FAR struct rwbuffer_s *rwb)
/* Allocate the read-ahead buffer */
rwb->rhallocsize = rwb->rhblocks * rwb->blocksize;
rwb->rhbuffer = malloc(rwb->rhallocsize);
if (!rwb->rhbuffer)
rwb->rhbuffer = NULL;
if (rwb->rhmaxblocks > 0)
{
fdbg("Read-ahead buffer malloc(%ld) failed\n", (long)rwb->rhallocsize);
return -ENOMEM;
allocsize = rwb->rhmaxblocks * rwb->blocksize;
rwb->rhbuffer = malloc(allocsize);
if (!rwb->rhbuffer)
{
fdbg("Read-ahead buffer malloc(%d) failed\n", allocsize);
return -ENOMEM;
}
}
fvdbg("Read-ahead buffer size: %d bytes\n", rwb->rhallocsize);
fvdbg("Read-ahead buffer size: %d bytes\n", allocsize);
#endif /* CONFIG_FS_READAHEAD */
return 0;
}
@ -470,11 +484,11 @@ void rwb_uninitialize(FAR struct rwbuffer_s *rwb)
* Name:
****************************************************************************/
int rwb_read(FAR struct rwbuffer_s *rwb, off_t startblock, uint32 blockcount,
int rwb_read(FAR struct rwbuffer_s *rwb, off_t startblock, uint32 nblocks,
FAR ubyte *rdbuffer)
{
fvdbg("startblock=%ld blockcount=%ld rdbuffer=%p",
(long)startblock, (long)blockcount, rdbuffer);
fvdbg("startblock=%ld nblocks=%ld rdbuffer=%p\n",
(long)startblock, (long)nblocks, rdbuffer);
#ifdef CONFIG_FS_WRITEBUFFER
/* If the new read data overlaps any part of the write buffer, then
@ -483,27 +497,30 @@ int rwb_read(FAR struct rwbuffer_s *rwb, off_t startblock, uint32 blockcount,
* is well-suited for simple streaming applications.
*/
/* If the write buffer overlaps the block(s) requested, then flush the
* write buffer.
*/
rwb_semtake(&rwb->wrsem);
if (rwb_overlap(rwb->wrblockstart, rwb->wrnbytes, startblock, blockcount))
if (rwb->wrmaxblocks > 0)
{
rwb_wrflush(rwb);
/* If the write buffer overlaps the block(s) requested, then flush the
* write buffer.
*/
rwb_semtake(&rwb->wrsem);
if (rwb_overlap(rwb->wrblockstart, rwb->wrnblocks, startblock, nblocks))
{
rwb_wrflush(rwb);
}
rwb_semgive(&rwb->wrsem);
}
rwb_semgive(&rwb->wrsem);
#endif
#ifdef CONFIG_FS_READAHEAD
/* Loop until we have read all of the requested blocks */
rwb_semtake(&rwb->rhsem);
while (blockcount > 0)
while (nblocks > 0)
{
/* Is there anything in the read-ahead buffer? */
if (rwb->rhnbytes > 0)
if (rwb->rhnblocks > 0)
{
off_t startblock = startblock;
size_t nblocks = 0;
@ -513,11 +530,11 @@ int rwb_read(FAR struct rwbuffer_s *rwb, off_t startblock, uint32 blockcount,
* number of buffers that we can read from read-ahead buffer.
*/
bufferend = rwb->rhblockstart + rwb->rhnbytes;
bufferend = rwb->rhblockstart + rwb->rhnblocks;
while ((startblock >= rwb->rhblockstart) &&
(startblock < bufferend) &&
(blockcount > 0))
(nblocks > 0))
{
/* This is one more that we will read from the read ahead buffer */
@ -526,7 +543,7 @@ int rwb_read(FAR struct rwbuffer_s *rwb, off_t startblock, uint32 blockcount,
/* And one less that we will read from the media */
startblock++;
blockcount--;
nblocks--;
}
/* Then read the data from the read-ahead buffer */
@ -538,12 +555,12 @@ int rwb_read(FAR struct rwbuffer_s *rwb, off_t startblock, uint32 blockcount,
* the buffer and try again.
*/
if (blockcount > 0)
if (nblocks > 0)
{
int ret = rwb_rhreload(rwb, startblock);
if (ret < 0)
{
fdbg("ERROR: Failed to fill the read-ahead buffer: %d", -ret);
fdbg("ERROR: Failed to fill the read-ahead buffer: %d\n", -ret);
return ret;
}
}
@ -552,7 +569,7 @@ int rwb_read(FAR struct rwbuffer_s *rwb, off_t startblock, uint32 blockcount,
rwb_semgive(&rwb->rhsem);
return 0;
#else
return rwb->rhreload(rwb->dev, startblock, blockcount, rdbuffer);
return rwb->rhreload(rwb->dev, startblock, nblocks, rdbuffer);
#endif
}
@ -561,7 +578,7 @@ int rwb_read(FAR struct rwbuffer_s *rwb, off_t startblock, uint32 blockcount,
****************************************************************************/
int rwb_write(FAR struct rwbuffer_s *rwb, off_t startblock,
size_t blockcount, FAR const ubyte *wrbuffer)
size_t nblocks, FAR const ubyte *wrbuffer)
{
int ret;
@ -573,7 +590,7 @@ int rwb_write(FAR struct rwbuffer_s *rwb, off_t startblock,
*/
rwb_semtake(&rwb->rhsem);
if (rwb_overlap(rwb->rhblockstart, rwb->rhnbytes, startblock, blockcount))
if (rwb_overlap(rwb->rhblockstart, rwb->rhnblocks, startblock, nblocks))
{
rwb_resetrhbuffer(rwb);
}
@ -581,11 +598,11 @@ int rwb_write(FAR struct rwbuffer_s *rwb, off_t startblock,
#endif
#ifdef CONFIG_FS_WRITEBUFFER
fvdbg("startblock=%d wrbuffer=%p", startblock, wrbuffer);
fvdbg("startblock=%d wrbuffer=%p\n", startblock, wrbuffer);
/* Use the block cache unless the buffer size is bigger than block cache */
if (blockcount > rwb->wrallocsize)
if (nblocks > rwb->wrmaxblocks)
{
/* First flush the cache */
@ -595,19 +612,19 @@ int rwb_write(FAR struct rwbuffer_s *rwb, off_t startblock,
/* Then transfer the data directly to the media */
ret = rwb->wrflush(rwb->dev, startblock, blockcount, wrbuffer);
ret = rwb->wrflush(rwb->dev, startblock, nblocks, wrbuffer);
}
else
{
/* Buffer the data in the write buffer */
ret = rwb_writebuffer(rwb, startblock, blockcount, wrbuffer);
ret = rwb_writebuffer(rwb, startblock, nblocks, wrbuffer);
}
return ret;
#else
return rwb->wrflush(rwb->dev, startblock, blockcount, wrbuffer);
return rwb->wrflush(rwb->dev, startblock, nblocks, wrbuffer);
#endif
}

33
include/nuttx/rwbuffer.h
View File

@ -66,9 +66,9 @@
*/
typedef ssize_t (*rwbreload_t)(FAR void *dev, FAR ubyte *buffer,
off_t start_sector, size_t nsectors);
off_t startblock, size_t nblocks);
typedef ssize_t (*rwbflush_t)(FAR void *dev, FAR const ubyte *buffer,
off_t start_sector, size_t nsectors);
off_t startblockr, size_t nblocks);
/* This structure holds the state of the buffers. In typical usage,
* an instance of this structure is declared within each block driver
@ -90,15 +90,17 @@ typedef ssize_t (*rwbflush_t)(FAR void *dev, FAR const ubyte *buffer,
*
* struct foo_dev_s *priv;
* ...
* ... [Setup blocksize, nblocks, dev, wrblocks, wrflush, rhblocks, rhreload] ...
* ... [Setup blocksize, nblocks, dev, wrmaxblocks, wrflush,
* rhmaxblocks, rhreload] ...
* ret = rwb_initialize(&priv->rwbuffer);
*/
struct rwbuffer_s
{
/********************************************************************/
/* These values must be provided by the user prior to calling rwb_initialize */
/* These values must be provided by the user prior to calling
* rwb_initialize()
*/
/* Supported geometry */
@ -106,12 +108,23 @@ struct rwbuffer_s
size_t nblocks; /* The total number blocks supported */
void *dev; /* Device state passed to callout functions */
/* Write buffer setup. If CONFIG_FS_WRITEBUFFER is defined, but you
* want read-ahead-only operation, (1) set wrmaxblocks to zero and do
* not use rwb_write().
*/
#ifdef CONFIG_FS_WRITEBUFFER
uint16 wrblocks; /* The number of blocks to buffer in memory */
uint16 wrmaxblocks; /* The number of blocks to buffer in memory */
rwbflush_t wrflush; /* Callout to flush the write buffer */
#endif
/* Read-ahead buffer setup. If CONFIG_FS_READAHEAD is defined but you
* want write-buffer-only operation, then (1) set rhmaxblocks to zero and
* do not use rwb_read().
*/
#ifdef CONFIG_FS_READAHEAD
uint16 rhblocks; /* The number of blocks to buffer in memory */
uint16 rhmaxblocks; /* The number of blocks to buffer in memory */
rwbreload_t rhreload; /* Callout to reload the read-ahead buffer */
#endif
@ -124,10 +137,9 @@ struct rwbuffer_s
sem_t wrsem; /* Enforces exclusive access to the write buffer */
struct work_s work; /* Delayed work to flush buffer after adelay with no activity */
ubyte *wrbuffer; /* Allocated write buffer */
size_t wrnbytes; /* Bytes in write buffer */
uint16 wrnblocks; /* Number of blocks in write buffer */
off_t wrblockstart; /* First block in write buffer */
off_t wrexpectedblock; /* Next block expected */
size_t wrallocsize; /* Size of allocated write buffer */
#endif
/* This is the state of the read-ahead buffer */
@ -135,9 +147,8 @@ struct rwbuffer_s
#ifdef CONFIG_FS_READAHEAD
sem_t rhsem; /* Enforces exclusive access to the write buffer */
ubyte *rhbuffer; /* Allocated read-ahead buffer */
size_t rhnbytes; /* Blocks in read-ahead buffer */
uint16 rhnblocks; /* Number of blocks in read-ahead buffer */
off_t rhblockstart; /* First block in read-ahead buffer */
size_t rhallocsize; /* Size of allocated read-ahead buffer */
#endif
};