| Message ID | 20210505075001.45041-10-vsementsov@virtuozzo.com |
|---|---|
| State | New |
| Headers | show |
| Series | 64bit block-layer: part II | expand |
On Wed, May 05, 2021 at 10:49:59AM +0300, Vladimir Sementsov-Ogievskiy wrote: > We are going to support 64 bit discard requests. Now update the > limit variable. It's absolutely safe. The variable is set in some > drivers, and used in bdrv_co_pdiscard(). > > Update also max_pdiscard variable in bdrv_co_pdiscard(), so that > bdrv_co_pdiscard() is now prepared to 64bit requests. The remaining s/to/for/ > logic including num, offset and bytes variables is already > supporting 64bit requests. > > So the only thing that prevents 64 bit requests is limiting > max_pdiscard variable to INT_MAX in bdrv_co_pdiscard(). > We'll drop this limitation after updating all block drivers. > > Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> > --- > include/block/block_int.h | 11 ++++++----- > block/io.c | 3 ++- > 2 files changed, 8 insertions(+), 6 deletions(-) > Deceptively simple for what it entails, but I agree that we are safe. Reviewed-by: Eric Blake <eblake@redhat.com>
diff --git a/include/block/block_int.h b/include/block/block_int.h index 5734f44e59..cb36ba93a6 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -664,11 +664,12 @@ typedef struct BlockLimits { * otherwise. */ uint32_t request_alignment; - /* Maximum number of bytes that can be discarded at once (since it - * is signed, it must be < 2G, if set). Must be multiple of - * pdiscard_alignment, but need not be power of 2. May be 0 if no - * inherent 32-bit limit */ - int32_t max_pdiscard; + /* + * Maximum number of bytes that can be discarded at once. Must be multiple + * of pdiscard_alignment, but need not be power of 2. May be 0 if no + * inherent 64-bit limit. + */ + int64_t max_pdiscard; /* Optimal alignment for discard requests in bytes. A power of 2 * is best but not mandatory. Must be a multiple of diff --git a/block/io.c b/block/io.c index 195b68b19e..a7edb1ef54 100644 --- a/block/io.c +++ b/block/io.c @@ -2991,7 +2991,8 @@ int coroutine_fn bdrv_co_pdiscard(BdrvChild *child, int64_t offset, int64_t bytes) { BdrvTrackedRequest req; - int max_pdiscard, ret; + int ret; + int64_t max_pdiscard; int head, tail, align; BlockDriverState *bs = child->bs;
We are going to support 64 bit discard requests. Now update the limit variable. It's absolutely safe. The variable is set in some drivers, and used in bdrv_co_pdiscard(). Update also max_pdiscard variable in bdrv_co_pdiscard(), so that bdrv_co_pdiscard() is now prepared to 64bit requests. The remaining logic including num, offset and bytes variables is already supporting 64bit requests. So the only thing that prevents 64 bit requests is limiting max_pdiscard variable to INT_MAX in bdrv_co_pdiscard(). We'll drop this limitation after updating all block drivers. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> --- include/block/block_int.h | 11 ++++++----- block/io.c | 3 ++- 2 files changed, 8 insertions(+), 6 deletions(-)