block: remove QUEUE_FLAG_DISCARD
Just use a non-zero max_discard_sectors as an indicator for discard
support, similar to what is done for write zeroes.
The only places where needs special attention is the RAID5 driver,
which must clear discard support for security reasons by default,
even if the default stacking rules would allow for it.
Signed-off-by: Christoph Hellwig <[email protected]>
Reviewed-by: Martin K. Petersen <[email protected]>
Acked-by: Christoph Böhmwalder <[email protected]> [drbd]
Acked-by: Jan Höppner <[email protected]> [s390]
Acked-by: Coly Li <[email protected]> [bcache]
Acked-by: David Sterba <[email protected]> [btrfs]
Reviewed-by: Chaitanya Kulkarni <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 4069f17..5d9cedf 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -2957,20 +2957,6 @@ static int setup_swap_map_and_extents(struct swap_info_struct *p,
return nr_extents;
}
-/*
- * Helper to sys_swapon determining if a given swap
- * backing device queue supports DISCARD operations.
- */
-static bool swap_discardable(struct swap_info_struct *si)
-{
- struct request_queue *q = bdev_get_queue(si->bdev);
-
- if (!blk_queue_discard(q))
- return false;
-
- return true;
-}
-
SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
{
struct swap_info_struct *p;
@@ -3132,7 +3118,8 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
sizeof(long),
GFP_KERNEL);
- if (p->bdev && (swap_flags & SWAP_FLAG_DISCARD) && swap_discardable(p)) {
+ if ((swap_flags & SWAP_FLAG_DISCARD) &&
+ p->bdev && bdev_max_discard_sectors(p->bdev)) {
/*
* When discard is enabled for swap with no particular
* policy flagged, we set all swap discard flags here in
