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Wed, 2 Sep 2026 04:55:49 +0000 (GMT) Message-ID: <94c6ccbb-0b76-43e1-b3a2-ef2fcb485ca5@linux.ibm.com> Date: Wed, 2 Sep 2026 10:25:48 +0530 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 1/2] nvme: keep transport module referenced while head node is open To: Keith Busch Cc: linux-nvme@lists.infradead.org, sagi@grimberg.me, hch@lst.de, axboe@fb.com, john.g.garry@oracle.com, wenxiong@linux.ibm.com, gjoyce@linux.ibm.com References: <20260831152006.819471-1-nilay@linux.ibm.com> <20260831152006.819471-2-nilay@linux.ibm.com> Content-Language: en-US From: Nilay Shroff In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Authority-Analysis: v=2.4 cv=EIc2FVZC c=1 sm=1 tr=0 ts=6a97ac5b cx=c_pps a=GFwsV6G8L6GxiO2Y/PsHdQ==:117 a=GFwsV6G8L6GxiO2Y/PsHdQ==:17 a=IkcTkHD0fZMA:10 a=VdqzKS8jKosA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=uAbxVGIbfxUO_5tXvNgY:22 a=pGKkRDS4hbavg4qZ3psA:9 a=QEXdDO2ut3YA:10 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwOTAyMDAzOCBTYWx0ZWRfX2aBXm3dgyRxy bssQaRUzXwPwQUP6h/ALqH5MRWs7mQe9YGvORbc66ii6SxULb41rfEPIrr1hp9d1B9bOy1D9DwC Rj6LuRdfuGGKl/r53aKfUMzgLXmmPSJzn7ACpYMYfU6KJzZt2RZys4b62DnDqKf98qiKc/ibC9L gQdde9eWxpJMx3r2fhTUlOPifB90lU6StGowR8flkSRk3wVeLxjvusuPwhyDZljktSqafuPFbBg 5IMXS764J8jAG6RJZ/6iUNUDjypzgViHUk9VqhpvOfSG2GT5we4bRbfxFQvTiO9d1E+QLDBZ92v t1kKfCNusnXviKBsgz1dz1ZFOoAxG1U4BIXu60dTfKAsvaAF64lokCTaGUw81Tx+N8FOjETvKIS yIp+Tt2SHNxwFhS5EJTSZrOYv0supdsXNW7kWvoC5BoaaRbM2GDqMh5rSKCrKCnJwl98vN9NEUN Kcp6LJvBvJH5ySR02OA== X-Proofpoint-GUID: mJ5H6RYYSoP6u5PXemNkKI_3GDCXG5I1 X-Proofpoint-ORIG-GUID: mJ5H6RYYSoP6u5PXemNkKI_3GDCXG5I1 X-Proofpoint-Spam-Info: AW1haW4tMjYwOTAyMDAzOCBTYWx0ZWRfX13X0HJqNWRXk wg5YLMZFENIVR+eAWf7fjOcFnaNIhfjp8H7KnnNRSMmnWUnVH8q7J+AJHcgkwW/2lCCFsiezjVd 7NRXWmPAR6H5hWCpw4TMxvROhkzIFP8= X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-09-01_06,2026-09-01_03,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 bulkscore=0 impostorscore=0 suspectscore=0 priorityscore=1501 clxscore=1015 phishscore=0 spamscore=0 adultscore=0 lowpriorityscore=0 malwarescore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2609020038 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260901_215607_624310_9A4C9E39 X-CRM114-Status: GOOD ( 18.64 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On 9/1/26 10:09 PM, Keith Busch wrote: > On Mon, Aug 31, 2026 at 08:49:54PM +0530, Nilay Shroff wrote: >> +static inline int nvme_module_get(struct nvme_ns *ns, unsigned int count) >> +{ >> + unsigned int i; >> + >> + for (i = 0; i < count; i++) { >> + if (!try_module_get(ns->ctrl->ops->module)) >> + goto out_unwind; >> + } >> + >> + return 0; >> +out_unwind: >> + while (i--) >> + module_put(ns->ctrl->ops->module); >> + return -ENXIO; >> +} >> + >> +static inline void nvme_module_put(struct nvme_ns *ns, unsigned int count) >> +{ >> + while (count--) >> + module_put(ns->ctrl->ops->module); >> +} > > Thanks, looks correct to me. > > I don't like the looping though. This could be done in a single > atomic_sub instead of multiple atomic_dec calls if the module api > provided something to get/put many references. Yeah I though of the same however unfortunately module APIs don't provide something using which we could atomically get/put more than one references. Thanks, --Nilay