From: Maurizio Lombardi Date: Fri, 29 Nov 2024 14:17:06 +0000 (+0100) Subject: nvme-fabrics: handle zero MAXCMD without closing the connection X-Git-Tag: nvme-6.13-2024-12-05~6 X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=88c23a32b851e36adc4ab36f796d9b711f47e2bb;p=nvme.git nvme-fabrics: handle zero MAXCMD without closing the connection The NVMe specification states that MAXCMD is mandatory for NVMe-over-Fabrics implementations. However, some NVMe/TCP and NVMe/FC arrays from major vendors have buggy firmware that reports MAXCMD as zero in the Identify Controller data structure. Currently, the implementation closes the connection in such cases, completely preventing the host from connecting to the target. Fix the issue by printing a clear error message about the firmware bug and allowing the connection to proceed. It assumes that the target supports a MAXCMD value of SQSIZE + 1. If any issues arise, the user can manually adjust SQSIZE to mitigate them. Fixes: 4999568184e5 ("nvme-fabrics: check max outstanding commands") Signed-off-by: Maurizio Lombardi Reviewed-by: Laurence Oberman Reviewed-by: Christoph Hellwig Signed-off-by: Keith Busch --- diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c index 5e5c9e15ad0c..1e904a794a4f 100644 --- a/drivers/nvme/host/core.c +++ b/drivers/nvme/host/core.c @@ -3233,8 +3233,9 @@ static int nvme_check_ctrl_fabric_info(struct nvme_ctrl *ctrl, struct nvme_id_ct } if (!ctrl->maxcmd) { - dev_err(ctrl->device, "Maximum outstanding commands is 0\n"); - return -EINVAL; + dev_warn(ctrl->device, + "Firmware bug: maximum outstanding commands is 0\n"); + ctrl->maxcmd = ctrl->sqsize + 1; } return 0;