scsi: storvsc: Ratelimit warning logs to prevent VM denial of service

If there's a persistent error in the hypervisor, the SCSI warning for
failed I/O can flood the kernel log and max out CPU utilization,
preventing troubleshooting from the VM side. Ratelimit the warning so
it doesn't DoS the VM.

Closes: https://github.com/microsoft/WSL/issues/9173
Signed-off-by: Easwar Hariharan <eahariha@linux.microsoft.com>
Link: https://lore.kernel.org/r/20250107-eahariha-ratelimit-storvsc-v1-1-7fc193d1f2b0@linux.microsoft.com
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c
index 45665d4aca925a10ce4293edf40cebdc4d4997f2..5a101ac06c478aad9b01072e7a6c5af48219f5c8 100644 (file)
--- a/drivers/scsi/storvsc_drv.c
+++ b/drivers/scsi/storvsc_drv.c
@@ -171,6 +171,12 @@ do {                                                               \
                dev_warn(&(dev)->device, fmt, ##__VA_ARGS__);   \
 } while (0)
 
+#define storvsc_log_ratelimited(dev, level, fmt, ...)                          \
+do {                                                                           \
+       if (do_logging(level))                                                  \
+               dev_warn_ratelimited(&(dev)->device, fmt, ##__VA_ARGS__);       \
+} while (0)
+
 struct vmscsi_request {
        u16 length;
        u8 srb_status;
@@ -1176,7 +1182,7 @@ static void storvsc_on_io_completion(struct storvsc_device *stor_device,
                int loglevel = (stor_pkt->vm_srb.cdb[0] == TEST_UNIT_READY) ?
                        STORVSC_LOGGING_WARN : STORVSC_LOGGING_ERROR;
 
-               storvsc_log(device, loglevel,
+               storvsc_log_ratelimited(device, loglevel,
                        "tag#%d cmd 0x%x status: scsi 0x%x srb 0x%x hv 0x%x\n",
                        scsi_cmd_to_rq(request->cmd)->tag,
                        stor_pkt->vm_srb.cdb[0],