From: =?UTF-8?q?Matias=20Bj=C3=B8rling?= <mb@lightnvm.io>
Date: Fri, 13 Jul 2018 10:48:41 +0200
Subject: [PATCH] lightnvm: limit get chunk meta request size
Git-commit: 59a8f43b6341b6964a9956640bb0f21b083ccd66
Patch-mainline: v4.19-rc1
References: bsc#1104967,FATE#325924
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
For devices that does not specify a limit on its transfer size, the
get_chk_meta command may send down a single I/O retrieving the full
chunk metadata table. Resulting in large 2-4MB I/O requests. Instead,
split up the I/Os to a maximum of 256KB and issue them separately to
reduce memory requirements.
Signed-off-by: Matias Bjørling <mb@lightnvm.io>
Reviewed-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Acked-by: Hannes Reinecke <hare@suse.com>
---
drivers/nvme/host/lightnvm.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/drivers/nvme/host/lightnvm.c b/drivers/nvme/host/lightnvm.c
index a76db8820f1c..d9e4cccd5b66 100644
--- a/drivers/nvme/host/lightnvm.c
+++ b/drivers/nvme/host/lightnvm.c
@@ -583,7 +583,13 @@ static int nvme_nvm_get_chk_meta(struct nvm_dev *ndev,
struct ppa_addr ppa;
size_t left = nchks * sizeof(struct nvme_nvm_chk_meta);
size_t log_pos, offset, len;
- int ret, i;
+ int ret, i, max_len;
+
+ /*
+ * limit requests to maximum 256K to avoid issuing arbitrary large
+ * requests when the device does not specific a maximum transfer size.
+ */
+ max_len = min_t(unsigned int, ctrl->max_hw_sectors << 9, 256 * 1024);
/* Normalize lba address space to obtain log offset */
ppa.ppa = slba;
@@ -596,7 +602,7 @@ static int nvme_nvm_get_chk_meta(struct nvm_dev *ndev,
offset = log_pos * sizeof(struct nvme_nvm_chk_meta);
while (left) {
- len = min_t(unsigned int, left, ctrl->max_hw_sectors << 9);
+ len = min_t(unsigned int, left, max_len);
ret = nvme_get_log_ext(ctrl, ns, NVME_NVM_LOG_REPORT_CHUNK,
dev_meta, len, offset);
--
2.12.3