On 11/19/23 15:29, Damien Le Moal wrote:
On 11/15/23 06:16, Bart Van Assche wrote:
@@ -82,6 +84,8 @@ void blk_set_stacking_limits(struct queue_limits *lim)
lim->max_dev_sectors = UINT_MAX;
lim->max_write_zeroes_sectors = UINT_MAX;
lim->max_zone_append_sectors = UINT_MAX;
+ /* Request-based stacking drivers do not reorder requests. */
Rereading this patch, I do not think this statement is correct. I seriously
doubt that multipath will preserve write command order in all cases...
+ lim->driver_preserves_write_order = true;
... so it is likely much safer to set the default to "false" as that is the
default for all requests in general.
How about applying this (untested) patch on top of this patch series?
diff --git a/block/blk-settings.c b/block/blk-settings.c
index 4c776c08f190..aba1972e9767 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -84,8 +84,6 @@ void blk_set_stacking_limits(struct queue_limits *lim)
lim->max_dev_sectors = UINT_MAX;
lim->max_write_zeroes_sectors = UINT_MAX;
lim->max_zone_append_sectors = UINT_MAX;
- /* Request-based stacking drivers do not reorder requests. */
- lim->driver_preserves_write_order = true;
}
EXPORT_SYMBOL(blk_set_stacking_limits);
diff --git a/drivers/md/dm-linear.c b/drivers/md/dm-linear.c
index 2d3e186ca87e..cb9abe4bd065 100644
--- a/drivers/md/dm-linear.c
+++ b/drivers/md/dm-linear.c
@@ -147,6 +147,11 @@ static int linear_report_zones(struct dm_target *ti,
#define linear_report_zones NULL
#endif
+static void linear_io_hints(struct dm_target *ti, struct queue_limits *limits)
+{
+ limits->driver_preserves_write_order = true;
+}
+
static int linear_iterate_devices(struct dm_target *ti,
iterate_devices_callout_fn fn, void *data)
{
@@ -208,6 +213,7 @@ static struct target_type linear_target = {
.map = linear_map,
.status = linear_status,
.prepare_ioctl = linear_prepare_ioctl,
+ .io_hints = linear_io_hints,
.iterate_devices = linear_iterate_devices,
.direct_access = linear_dax_direct_access,
.dax_zero_page_range = linear_dax_zero_page_range,
@@ -685,6 +689,10 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
b->max_secure_erase_sectors);
t->zone_write_granularity = max(t->zone_write_granularity,
b->zone_write_granularity);
+ t->driver_preserves_write_order = t->driver_preserves_write_order &&
+ b->driver_preserves_write_order;
+ t->use_zone_write_lock = t->use_zone_write_lock ||
+ b->use_zone_write_lock;
Very minor nit: splitting the line after the equal would make this more readable.
Hmm ... I have often seen other reviewers asking to maximize the use of each
source code line as much as reasonably possible.
Thanks,
Bart.
