Linux 5.19 compat: bdev_max_discard_sectors()

Linux 5.19 commit torvalds/linux@70200574cc removed the
blk_queue_discard() helper function.  The preferred interface
is to now use the bdev_max_discard_sectors() function to check
for discard support.

Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #13515

config/kernel-blk-queue.m4

@@ -74,6 +74,8 @@ AC_DEFUN([ZFS_AC_KERNEL_BLK_QUEUE_UPDATE_READAHEAD], [
 		AC_DEFINE(HAVE_BLK_QUEUE_UPDATE_READAHEAD, 1,
 		    [blk_queue_update_readahead() exists])
 	],[
+		AC_MSG_RESULT(no)
+
 		AC_MSG_CHECKING([whether disk_update_readahead() exists])
 		ZFS_LINUX_TEST_RESULT([disk_update_readahead], [
 			AC_MSG_RESULT(yes)
@@ -86,10 +88,19 @@ AC_DEFUN([ZFS_AC_KERNEL_BLK_QUEUE_UPDATE_READAHEAD], [
 ])
 
 dnl #
-dnl # 2.6.32 API,
+dnl # 5.19: bdev_max_discard_sectors() available
-dnl #   blk_queue_discard()
+dnl # 2.6.32: blk_queue_discard() available
 dnl #
 AC_DEFUN([ZFS_AC_KERNEL_SRC_BLK_QUEUE_DISCARD], [
+	ZFS_LINUX_TEST_SRC([bdev_max_discard_sectors], [
+		#include <linux/blkdev.h>
+	],[
+		struct block_device *bdev __attribute__ ((unused)) = NULL;
+		unsigned int error __attribute__ ((unused));
+
+		error = bdev_max_discard_sectors(bdev);
+	])
+
 	ZFS_LINUX_TEST_SRC([blk_queue_discard], [
 		#include <linux/blkdev.h>
 	],[
@@ -102,11 +113,22 @@ AC_DEFUN([ZFS_AC_KERNEL_SRC_BLK_QUEUE_DISCARD], [
 ])
 
 AC_DEFUN([ZFS_AC_KERNEL_BLK_QUEUE_DISCARD], [
-	AC_MSG_CHECKING([whether blk_queue_discard() is available])
+	AC_MSG_CHECKING([whether bdev_max_discard_sectors() is available])
-	ZFS_LINUX_TEST_RESULT([blk_queue_discard], [
+	ZFS_LINUX_TEST_RESULT([bdev_max_discard_sectors], [
 		AC_MSG_RESULT(yes)
+		AC_DEFINE(HAVE_BDEV_MAX_DISCARD_SECTORS, 1,
+		    [bdev_max_discard_sectors() is available])
 	],[
-		ZFS_LINUX_TEST_ERROR([blk_queue_discard])
+		AC_MSG_RESULT(no)
+
+		AC_MSG_CHECKING([whether blk_queue_discard() is available])
+		ZFS_LINUX_TEST_RESULT([blk_queue_discard], [
+			AC_MSG_RESULT(yes)
+			AC_DEFINE(HAVE_BLK_QUEUE_DISCARD, 1,
+			    [blk_queue_discard() is available])
+		],[
+			ZFS_LINUX_TEST_ERROR([blk_queue_discard])
+		])
 	])
 ])
 

config/kernel-vfs-iov_iter.m4

@@ -134,6 +134,8 @@ AC_DEFUN([ZFS_AC_KERNEL_VFS_IOV_ITER], [
 		AC_DEFINE(HAVE_IOV_ITER_FAULT_IN_READABLE, 1,
 		    [iov_iter_fault_in_readable() is available])
 	],[
+		AC_MSG_RESULT(no)
+
 		AC_MSG_CHECKING([whether fault_in_iov_iter_readable() is available])
 		ZFS_LINUX_TEST_RESULT([fault_in_iov_iter_readable], [
 			AC_MSG_RESULT(yes)

include/os/linux/kernel/linux/blkdev_compat.h

@@ -494,6 +494,25 @@ blk_queue_discard_granularity(struct request_queue *q, unsigned int dg)
 	q->limits.discard_granularity = dg;
 }
 
+/*
+ * 5.19 API,
+ *   bdev_max_discard_sectors()
+ *
+ * 2.6.32 API,
+ *   blk_queue_discard()
+ */
+static inline boolean_t
+bdev_discard_supported(struct block_device *bdev)
+{
+#if defined(HAVE_BDEV_MAX_DISCARD_SECTORS)
+	return (!!bdev_max_discard_sectors(bdev));
+#elif defined(HAVE_BLK_QUEUE_DISCARD)
+	return (!!blk_queue_discard(bdev_get_queue(bdev)));
+#else
+#error "Unsupported kernel"
+#endif
+}
+
 /*
  * 4.8 API,
  *   blk_queue_secure_erase()

module/os/linux/zfs/vdev_disk.c

@@ -316,7 +316,7 @@ vdev_disk_open(vdev_t *v, uint64_t *psize, uint64_t *max_psize,
 	v->vdev_nowritecache = B_FALSE;
 
 	/* Set when device reports it supports TRIM. */
-	v->vdev_has_trim = !!blk_queue_discard(q);
+	v->vdev_has_trim = bdev_discard_supported(vd->vd_bdev);
 
 	/* Set when device reports it supports secure TRIM. */
 	v->vdev_has_securetrim = !!blk_queue_discard_secure(q);

module/os/linux/zfs/zvol_os.c

@@ -1053,7 +1053,9 @@ zvol_os_create_minor(const char *name)
 	    (zvol_max_discard_blocks * zv->zv_volblocksize) >> 9);
 	blk_queue_discard_granularity(zv->zv_zso->zvo_queue,
 	    zv->zv_volblocksize);
+#ifdef QUEUE_FLAG_DISCARD
 	blk_queue_flag_set(QUEUE_FLAG_DISCARD, zv->zv_zso->zvo_queue);
+#endif
 #ifdef QUEUE_FLAG_NONROT
 	blk_queue_flag_set(QUEUE_FLAG_NONROT, zv->zv_zso->zvo_queue);
 #endif