From 14e2593dd6242d12c522c5fd4515e3182a2fe6e9 Mon Sep 17 00:00:00 2001 From: Brian Behlendorf Date: Mon, 21 Dec 2020 10:11:56 -0800 Subject: [PATCH] Linux 4.18.0-257.el8 compat: blk_alloc_queue() The CentOS stream 4.18.0-257 kernel appears to have backported the Linux 5.9 change to make_request_fn and the associated API. To maintain weak modules compatibility the original symbol was retained and the new interface blk_alloc_queue_rh() was added. Unfortunately, blk_alloc_queue() was replaced in the blkdev.h header by blk_alloc_queue_bh() so there doesn't seem to be a way to build new kmods against the old interfces. Even though they appear to still be available for weak module binding. To accommodate this a configure check is added for the new _rh() variant of the function and used if available. If compatibility code gets added to the kernel for the original blk_alloc_queue() interface this should be fine. OpenZFS will simply continue to prefer the new interface and only fallback to blk_alloc_queue() when blk_alloc_queue_rh() isn't available. Signed-off-by: Brian Behlendorf Closes #11374 --- config/kernel-make-request-fn.m4 | 73 ++++++++++++++----- include/os/linux/kernel/linux/blkdev_compat.h | 2 + 2 files changed, 58 insertions(+), 17 deletions(-) diff --git a/config/kernel-make-request-fn.m4 b/config/kernel-make-request-fn.m4 index 1576fece1368..290ef6b8da7d 100644 --- a/config/kernel-make-request-fn.m4 +++ b/config/kernel-make-request-fn.m4 @@ -27,6 +27,15 @@ AC_DEFUN([ZFS_AC_KERNEL_SRC_MAKE_REQUEST_FN], [ q = blk_alloc_queue(make_request, NUMA_NO_NODE); ]) + ZFS_LINUX_TEST_SRC([blk_alloc_queue_request_fn_rh], [ + #include + blk_qc_t make_request(struct request_queue *q, + struct bio *bio) { return (BLK_QC_T_NONE); } + ],[ + struct request_queue *q __attribute__ ((unused)); + q = blk_alloc_queue_rh(make_request, NUMA_NO_NODE); + ]) + ZFS_LINUX_TEST_SRC([block_device_operations_submit_bio], [ #include ],[ @@ -47,7 +56,9 @@ AC_DEFUN([ZFS_AC_KERNEL_MAKE_REQUEST_FN], [ AC_DEFINE(HAVE_SUBMIT_BIO_IN_BLOCK_DEVICE_OPERATIONS, 1, [submit_bio is member of struct block_device_operations]) - ],[ + ],[ + AC_MSG_RESULT(no) + dnl # Checked as part of the blk_alloc_queue_request_fn test dnl # dnl # Linux 5.7 API Change @@ -55,6 +66,9 @@ AC_DEFUN([ZFS_AC_KERNEL_MAKE_REQUEST_FN], [ dnl # AC_MSG_CHECKING([whether blk_alloc_queue() expects request function]) ZFS_LINUX_TEST_RESULT([blk_alloc_queue_request_fn], [ + AC_MSG_RESULT(yes) + + dnl # This is currently always the case. AC_MSG_CHECKING([whether make_request_fn() returns blk_qc_t]) AC_MSG_RESULT(yes) @@ -66,34 +80,59 @@ AC_DEFUN([ZFS_AC_KERNEL_MAKE_REQUEST_FN], [ [Noting that make_request_fn() returns blk_qc_t]) ],[ dnl # - dnl # Linux 3.2 API Change - dnl # make_request_fn returns void. + dnl # CentOS Stream 4.18.0-257 API Change + dnl # The Linux 5.7 blk_alloc_queue() change was back- + dnl # ported and the symbol renamed blk_alloc_queue_rh(). + dnl # As of this kernel version they're not providing + dnl # any compatibility code in the kernel for this. dnl # - AC_MSG_CHECKING([whether make_request_fn() returns void]) - ZFS_LINUX_TEST_RESULT([make_request_fn_void], [ + ZFS_LINUX_TEST_RESULT([blk_alloc_queue_request_fn_rh], [ AC_MSG_RESULT(yes) - AC_DEFINE(MAKE_REQUEST_FN_RET, void, + + dnl # This is currently always the case. + AC_MSG_CHECKING([whether make_request_fn_rh() returns blk_qc_t]) + AC_MSG_RESULT(yes) + + AC_DEFINE(HAVE_BLK_ALLOC_QUEUE_REQUEST_FN_RH, 1, + [blk_alloc_queue_rh() expects request function]) + AC_DEFINE(MAKE_REQUEST_FN_RET, blk_qc_t, [make_request_fn() return type]) - AC_DEFINE(HAVE_MAKE_REQUEST_FN_RET_VOID, 1, - [Noting that make_request_fn() returns void]) + AC_DEFINE(HAVE_MAKE_REQUEST_FN_RET_QC, 1, + [Noting that make_request_fn() returns blk_qc_t]) ],[ AC_MSG_RESULT(no) dnl # - dnl # Linux 4.4 API Change - dnl # make_request_fn returns blk_qc_t. + dnl # Linux 3.2 API Change + dnl # make_request_fn returns void. dnl # AC_MSG_CHECKING( - [whether make_request_fn() returns blk_qc_t]) - ZFS_LINUX_TEST_RESULT([make_request_fn_blk_qc_t], [ + [whether make_request_fn() returns void]) + ZFS_LINUX_TEST_RESULT([make_request_fn_void], [ AC_MSG_RESULT(yes) - AC_DEFINE(MAKE_REQUEST_FN_RET, blk_qc_t, + AC_DEFINE(MAKE_REQUEST_FN_RET, void, [make_request_fn() return type]) - AC_DEFINE(HAVE_MAKE_REQUEST_FN_RET_QC, 1, - [Noting that make_request_fn() ] - [returns blk_qc_t]) + AC_DEFINE(HAVE_MAKE_REQUEST_FN_RET_VOID, 1, + [Noting that make_request_fn() returns void]) ],[ - ZFS_LINUX_TEST_ERROR([make_request_fn]) + AC_MSG_RESULT(no) + + dnl # + dnl # Linux 4.4 API Change + dnl # make_request_fn returns blk_qc_t. + dnl # + AC_MSG_CHECKING( + [whether make_request_fn() returns blk_qc_t]) + ZFS_LINUX_TEST_RESULT([make_request_fn_blk_qc_t], [ + AC_MSG_RESULT(yes) + AC_DEFINE(MAKE_REQUEST_FN_RET, blk_qc_t, + [make_request_fn() return type]) + AC_DEFINE(HAVE_MAKE_REQUEST_FN_RET_QC, 1, + [Noting that make_request_fn() ] + [returns blk_qc_t]) + ],[ + ZFS_LINUX_TEST_ERROR([make_request_fn]) + ]) ]) ]) ]) diff --git a/include/os/linux/kernel/linux/blkdev_compat.h b/include/os/linux/kernel/linux/blkdev_compat.h index 35b7756336a2..220344c814f9 100644 --- a/include/os/linux/kernel/linux/blkdev_compat.h +++ b/include/os/linux/kernel/linux/blkdev_compat.h @@ -529,6 +529,8 @@ blk_generic_alloc_queue(make_request_fn make_request, int node_id) { #if defined(HAVE_BLK_ALLOC_QUEUE_REQUEST_FN) return (blk_alloc_queue(make_request, node_id)); +#elif defined(HAVE_BLK_ALLOC_QUEUE_REQUEST_FN_RH) + return (blk_alloc_queue_rh(make_request, node_id)); #else struct request_queue *q = blk_alloc_queue(GFP_KERNEL); if (q != NULL)