dm-crypt: enable DM_TARGET_ATOMIC_WRITES

Allow handling of bios with REQ_ATOMIC flag set.

Don't split these bios and fail them if they overrun the hard limit
"BIO_MAX_VECS << PAGE_SHIFT".

In order to simplify the code, this commit joins the logic that avoids
splitting emulated zone append bios with the logic that avoids
splitting atomic write bios.

Signed-off-by: John Garry <john.g.garry@oracle.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Tested-by: John Garry <john.g.garry@oracle.com>

diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index 5eace7d4a67a0f52c5afdbfe3482026da63a821e..79704fbc523b5a45dd8fa68d300853b2bf4722e0 100644 (file)
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -254,22 +254,15 @@ static unsigned int max_write_size = 0;
 module_param(max_write_size, uint, 0644);
 MODULE_PARM_DESC(max_write_size, "Maximum size of a write request");
 
-static unsigned get_max_request_sectors(struct dm_target *ti, struct bio *bio)
+static unsigned get_max_request_sectors(struct dm_target *ti, struct bio *bio, bool no_split)
 {
        struct crypt_config *cc = ti->private;
        unsigned val, sector_align;
        bool wrt = op_is_write(bio_op(bio));
 
-       if (wrt) {
-               /*
-                * For zoned devices, splitting write operations creates the
-                * risk of deadlocking queue freeze operations with zone write
-                * plugging BIO work when the reminder of a split BIO is
-                * issued. So always allow the entire BIO to proceed.
-                */
-               if (ti->emulate_zone_append)
-                       return bio_sectors(bio);
-
+       if (no_split) {
+               val = -1;
+       } else if (wrt) {
                val = min_not_zero(READ_ONCE(max_write_size),
                                   DM_CRYPT_DEFAULT_MAX_WRITE_SIZE);
        } else {
@@ -3462,6 +3455,7 @@ static int crypt_map(struct dm_target *ti, struct bio *bio)
        struct dm_crypt_io *io;
        struct crypt_config *cc = ti->private;
        unsigned max_sectors;
+       bool no_split;
 
        /*
         * If bio is REQ_PREFLUSH or REQ_OP_DISCARD, just bypass crypt queues.
@@ -3479,10 +3473,20 @@ static int crypt_map(struct dm_target *ti, struct bio *bio)
 
        /*
         * Check if bio is too large, split as needed.
+        *
+        * For zoned devices, splitting write operations creates the
+        * risk of deadlocking queue freeze operations with zone write
+        * plugging BIO work when the reminder of a split BIO is
+        * issued. So always allow the entire BIO to proceed.
         */
-       max_sectors = get_max_request_sectors(ti, bio);
-       if (unlikely(bio_sectors(bio) > max_sectors))
+       no_split = (ti->emulate_zone_append && op_is_write(bio_op(bio))) ||
+                  (bio->bi_opf & REQ_ATOMIC);
+       max_sectors = get_max_request_sectors(ti, bio, no_split);
+       if (unlikely(bio_sectors(bio) > max_sectors)) {
+               if (unlikely(no_split))
+                       return DM_MAPIO_KILL;
                dm_accept_partial_bio(bio, max_sectors);
+       }
 
        /*
         * Ensure that bio is a multiple of internal sector encryption size
@@ -3728,15 +3732,20 @@ static void crypt_io_hints(struct dm_target *ti, struct queue_limits *limits)
        if (ti->emulate_zone_append)
                limits->max_hw_sectors = min(limits->max_hw_sectors,
                                             BIO_MAX_VECS << PAGE_SECTORS_SHIFT);
+
+       limits->atomic_write_hw_unit_max = min(limits->atomic_write_hw_unit_max,
+                                              BIO_MAX_VECS << PAGE_SHIFT);
+       limits->atomic_write_hw_max = min(limits->atomic_write_hw_max,
+                                         BIO_MAX_VECS << PAGE_SHIFT);
 }
 
 static struct target_type crypt_target = {
        .name   = "crypt",
-       .version = {1, 28, 0},
+       .version = {1, 29, 0},
        .module = THIS_MODULE,
        .ctr    = crypt_ctr,
        .dtr    = crypt_dtr,
-       .features = DM_TARGET_ZONED_HM,
+       .features = DM_TARGET_ZONED_HM | DM_TARGET_ATOMIC_WRITES,
        .report_zones = crypt_report_zones,
        .map    = crypt_map,
        .status = crypt_status,