[RFC][PATCH] nvme/core: Notify udev about capacity change

[Balbir Singh <sblbir@amazon.com>]

From: Someswarudu Sangaraju <ssomesh@amazon.com>

NVME capacity can change asynchronously via NVME_AER_NOTICE_NS_CHANGED
The current stack does the right thing and resizes the disk via
set_capacity() called from nvme_update_disk_info(). This patch adds
a user space notification via uevent to let udev know that a resize
occurred if the capacity changes.

Signed-off-by: Someswarudu Sangaraju <ssomesh@amazon.com>
[Balbir - send the notification only on capacity change and wrote the
changelog]
Signed-off-by: Balbir Singh <sblbir@amazon.com>
---
 drivers/nvme/host/core.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index dfe37a525f3a..a413aee3107d 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -1757,6 +1757,7 @@ static void nvme_update_disk_info(struct gendisk *disk,
 		struct nvme_ns *ns, struct nvme_id_ns *id)
 {
 	sector_t capacity = nvme_lba_to_sect(ns, le64_to_cpu(id->nsze));
+	sector_t old_capacity = get_capacity(disk);
 	unsigned short bs = 1 << ns->lba_shift;
 	u32 atomic_bs, phys_bs, io_opt;
 
@@ -1807,6 +1808,11 @@ static void nvme_update_disk_info(struct gendisk *disk,
 		capacity = 0;
 
 	set_capacity(disk, capacity);
+	if (old_capacity != capacity) {
+		char *envp[] = { "RESIZE=1", NULL };
+
+		kobject_uevent_env(&disk_to_dev(disk)->kobj, KOBJ_CHANGE, envp);
+	}
 
 	nvme_config_discard(disk, ns);
 	nvme_config_write_zeroes(disk, ns);
-- 
2.16.5


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