On 6/4/19 6:06 PM, Ming Lei wrote:
If user doesn't ask to pre-allocate by passing zero 'nents_first_chunk' to
sg_alloc_table_chained, we need to make sure that 'first_chunk' is cleared.
Otherwise, __sg_alloc_table() still may think that the 1st SGL should
be from the pre-allocation.
Fixes the issue by clearing 'first_chunk' in sg_alloc_table_chained() if
'nents_first_chunk' is zero.
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Bart Van Assche <bvanassche@xxxxxxx>
Cc: Ewan D. Milne <emilne@xxxxxxxxxx>
Cc: Hannes Reinecke <hare@xxxxxxxx>
Cc: Guenter Roeck <linux@xxxxxxxxxxxx>
Fixes: c3288dd8c232 ("scsi: core: avoid pre-allocating big SGL for data")
Shouldn't the "Fixes:" tag be left out from this patch? I don't think
that this patch by itself fixes anything. Isn't this patch something
that is necessary to make patch 2/3 in this series work? How about
indicating that by mentioning it in the commit message?
Reported-by: Guenter Roeck <linux@xxxxxxxxxxxx>
Tested-by: Guenter Roeck <linux@xxxxxxxxxxxx>
Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
---
lib/sg_pool.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/lib/sg_pool.c b/lib/sg_pool.c
index 47eecbe094d8..e042a1722615 100644
--- a/lib/sg_pool.c
+++ b/lib/sg_pool.c
@@ -122,7 +122,7 @@ int sg_alloc_table_chained(struct sg_table *table, int nents,
}
/* User supposes that the 1st SGL includes real entry */
- if (nents_first_chunk == 1) {
+ if (nents_first_chunk <= 1) {
first_chunk = NULL;
nents_first_chunk = 0;
}
How about also updating the kernel-doc header above
sg_alloc_table_chained() such that it is made clear that @first_chunk is
ignored if nents_first_chunk <= 1 ? Otherwise this patch looks fine to me.
Bart.
