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[SCSI] st: fix mdata->page_order handling

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dio transfer always resets mdata->page_order to zero. It breaks
high-order pages previously allocated for non-dio transfer.

This patches adds reserved_page_order to st_buffer structure to save
page order for non-dio transfer.

http://bugzilla.kernel.org/show_bug.cgi?id=14563

When enlarge_buffer() allocates 524288 from 0, st uses six-order page
allocation. So mdata->page_order is 6 and frp_seg is 2.

After that, if st uses dio, sgl_map_user_pages() sets
mdata->page_order to 0 for st_do_scsi(). After that, when we call
normalize_buffer(), it frees only free frp_seg * PAGE_SIZE (2 * 4096)
though we should free frp_seg * PAGE_SIZE << 6 (2 * 4096 << 6). So we
see buffer_size is set to 516096 (524288 - 8192).

Reported-by: Joachim Breuer <linux-kernel@jmbreuer.net>
Tested-by: Joachim Breuer <linux-kernel@jmbreuer.net>
Acked-by: Kai Makisara <kai.makisara@kolumbus.fi>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: stable@kernel.org
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
This commit is contained in:
FUJITA Tomonori 2009-11-26 09:24:13 +09:00 committed by James Bottomley
parent 78b9fb6d38
commit c982c368bb
2 changed files with 13 additions and 11 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

23
drivers/scsi/st.c
View file

@ -552,13 +552,15 @@ st_do_scsi(struct st_request * SRpnt, struct scsi_tape * STp, unsigned char *cmd
SRpnt->waiting = waiting;
if (STp->buffer->do_dio) {
mdata->page_order = 0;
mdata->nr_entries = STp->buffer->sg_segs;
mdata->pages = STp->buffer->mapped_pages;
} else {
mdata->page_order = STp->buffer->reserved_page_order;
mdata->nr_entries =
DIV_ROUND_UP(bytes, PAGE_SIZE << mdata->page_order);
STp->buffer->map_data.pages = STp->buffer->reserved_pages;
STp->buffer->map_data.offset = 0;
mdata->pages = STp->buffer->reserved_pages;
mdata->offset = 0;
}
memcpy(SRpnt->cmd, cmd, sizeof(SRpnt->cmd));
@ -3719,7 +3721,7 @@ static int enlarge_buffer(struct st_buffer * STbuffer, int new_size, int need_dm
priority |= __GFP_ZERO;
if (STbuffer->frp_segs) {
order = STbuffer->map_data.page_order;
order = STbuffer->reserved_page_order;
b_size = PAGE_SIZE << order;
} else {
for (b_size = PAGE_SIZE, order = 0;
@ -3752,7 +3754,7 @@ static int enlarge_buffer(struct st_buffer * STbuffer, int new_size, int need_dm
segs++;
}
STbuffer->b_data = page_address(STbuffer->reserved_pages[0]);
STbuffer->map_data.page_order = order;
STbuffer->reserved_page_order = order;
return 1;
}
@ -3765,7 +3767,7 @@ static void clear_buffer(struct st_buffer * st_bp)
for (i=0; i < st_bp->frp_segs; i++)
memset(page_address(st_bp->reserved_pages[i]), 0,
PAGE_SIZE << st_bp->map_data.page_order);
PAGE_SIZE << st_bp->reserved_page_order);
st_bp->cleared = 1;
}
@ -3773,7 +3775,7 @@ static void clear_buffer(struct st_buffer * st_bp)
/* Release the extra buffer */
static void normalize_buffer(struct st_buffer * STbuffer)
{
int i, order = STbuffer->map_data.page_order;
int i, order = STbuffer->reserved_page_order;
for (i = 0; i < STbuffer->frp_segs; i++) {
__free_pages(STbuffer->reserved_pages[i], order);
@ -3781,7 +3783,7 @@ static void normalize_buffer(struct st_buffer * STbuffer)
}
STbuffer->frp_segs = 0;
STbuffer->sg_segs = 0;
STbuffer->map_data.page_order = 0;
STbuffer->reserved_page_order = 0;
STbuffer->map_data.offset = 0;
}
@ -3791,7 +3793,7 @@ static void normalize_buffer(struct st_buffer * STbuffer)
static int append_to_buffer(const char __user *ubp, struct st_buffer * st_bp, int do_count)
{
int i, cnt, res, offset;
int length = PAGE_SIZE << st_bp->map_data.page_order;
int length = PAGE_SIZE << st_bp->reserved_page_order;
for (i = 0, offset = st_bp->buffer_bytes;
i < st_bp->frp_segs && offset >= length; i++)
@ -3823,7 +3825,7 @@ static int append_to_buffer(const char __user *ubp, struct st_buffer * st_bp, in
static int from_buffer(struct st_buffer * st_bp, char __user *ubp, int do_count)
{
int i, cnt, res, offset;
int length = PAGE_SIZE << st_bp->map_data.page_order;
int length = PAGE_SIZE << st_bp->reserved_page_order;
for (i = 0, offset = st_bp->read_pointer;
i < st_bp->frp_segs && offset >= length; i++)
@ -3856,7 +3858,7 @@ static void move_buffer_data(struct st_buffer * st_bp, int offset)
{
int src_seg, dst_seg, src_offset = 0, dst_offset;
int count, total;
int length = PAGE_SIZE << st_bp->map_data.page_order;
int length = PAGE_SIZE << st_bp->reserved_page_order;
if (offset == 0)
return;
@ -4578,7 +4580,6 @@ static int sgl_map_user_pages(struct st_buffer *STbp,
}
mdata->offset = uaddr & ~PAGE_MASK;
mdata->page_order = 0;
STbp->mapped_pages = pages;
return nr_pages;

1
drivers/scsi/st.h
View file

@ -46,6 +46,7 @@ struct st_buffer {
struct st_request *last_SRpnt;
struct st_cmdstatus cmdstat;
struct page **reserved_pages;
int reserved_page_order;
struct page **mapped_pages;
struct rq_map_data map_data;
unsigned char *b_data;