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device: Rearrange _aligned_io().

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This commit is contained in:
Alasdair G Kergon 2018-01-15 19:59:28 +00:00
parent c90582344d
commit b825987b2f
1 changed files with 35 additions and 38 deletions
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73
lib/device/dev-io.c
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@ -261,10 +261,9 @@ static void _widen_region(unsigned int block_size, struct device_area *region,
result->size += block_size - delta;
}
static int _aligned_io(struct device_area *where, char *buffer,
static int _aligned_io(struct device_area *where, char *write_buffer,
int should_write, dev_io_reason_t reason)
{
char *bounce, *bounce_buf = NULL;
unsigned int physical_block_size = 0;
unsigned int block_size = 0;
unsigned buffer_was_widened = 0;
@ -295,18 +294,30 @@ static int _aligned_io(struct device_area *where, char *buffer,
where->size, (uint64_t) where->start, widened.size, (uint64_t) widened.start, dev_name(where->dev), _reason_text(reason));
}
if (should_write && !buffer_was_widened && !((uintptr_t) buffer & mask))
devbuf = DEV_DEVBUF(where->dev, reason);
_release_devbuf(devbuf);
devbuf->where.dev = where->dev;
devbuf->where.start = widened.start;
devbuf->where.size = widened.size;
devbuf->write = should_write;
devbuf->reason = reason;
/* Store location of requested data relative to start of buf */
devbuf->data_offset = where->start - devbuf->where.start;
if (should_write && !buffer_was_widened && !((uintptr_t) write_buffer & mask)) {
/* Perform the I/O directly. */
bounce = buffer;
devbuf->buf = write_buffer;
devbuf->malloc_address = NULL;
#ifndef DEBUG_MEM
else if (!(bounce_buf = bounce = dm_malloc_aligned((size_t) widened.size, 0))) {
} else if (!(devbuf->malloc_address = devbuf->buf = dm_malloc_aligned((size_t) devbuf->where.size, 0))) {
log_error("Bounce buffer malloc failed");
return 0;
}
#else
else {
} else {
/* Allocate a bounce buffer with an extra block */
if (!(bounce_buf = bounce = dm_malloc((size_t) widened.size + block_size))) {
if (!(devbuf->malloc_address = devbuf->buf = dm_malloc((size_t) devbuf->where.size + block_size))) {
log_error("Bounce buffer malloc failed");
return 0;
}
@ -314,53 +325,39 @@ static int _aligned_io(struct device_area *where, char *buffer,
/*
* Realign start of bounce buffer (using the extra sector)
*/
if (((uintptr_t) bounce) & mask)
bounce = (char *) ((((uintptr_t) bounce) + mask) & ~mask);
if (((uintptr_t) devbuf->buf) & mask)
devbuf->buf = (char *) ((((uintptr_t) devbuf->buf) + mask) & ~mask);
}
#endif
devbuf = DEV_DEVBUF(where->dev, reason);
_release_devbuf(devbuf);
devbuf->malloc_address = bounce_buf;
devbuf->buf = bounce;
devbuf->where.dev = where->dev;
devbuf->where.start = widened.start;
devbuf->where.size = widened.size;
devbuf->write = 0;
devbuf->reason = reason;
/* Do we need to read into the bounce buffer? */
if ((!should_write || buffer_was_widened) &&
!_io(devbuf)) {
if ((!should_write || buffer_was_widened) && !_io(devbuf)) {
if (!should_write)
goto_bad;
/* FIXME Handle errors properly! */
/* FIXME pre-extend the file */
memset(bounce, '\n', widened.size);
memset(devbuf->buf, '\n', devbuf->where.size);
}
if (should_write) {
if (bounce_buf) {
memcpy(bounce + (where->start - widened.start), buffer,
(size_t) where->size);
log_debug_io("Overwriting %" PRIu64 " bytes at %" PRIu64 " (for %s)", where->size,
(uint64_t) where->start, _reason_text(reason));
}
/* ... then we write */
devbuf->write = 1;
if (!(r = _io(devbuf)))
goto_bad;
_release_devbuf(devbuf);
if (!should_write)
return 1;
/* writes */
if (devbuf->malloc_address) {
memcpy((char *) devbuf->buf + devbuf->data_offset, write_buffer, (size_t) where->size);
log_debug_io("Overwriting %" PRIu64 " bytes at %" PRIu64 " (for %s)", where->size,
(uint64_t) where->start, _reason_text(devbuf->reason));
}
/* read */
/* We store what we just read as it often also satisfies the next request */
devbuf->data_offset = where->start - widened.start;
/* ... then we write */
devbuf->write = 1;
if (!(r = _io(devbuf)))
goto_bad;
_release_devbuf(devbuf);
return 1;
bad: