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Fri, 25 Sep 2026 06:01:32 -0400 (EDT) Date: Fri, 25 Sep 2026 11:01:31 +0100 From: Kiryl Shutsemau To: Jason Gunthorpe Cc: Will Deacon , Robin Murphy , Joerg Roedel , Nicolin Chen , Pranjal Shrivastava , Mostafa Saleh , Thierry Reding , Krishna Reddy , Jonathan Hunter , Breno Leitao , Kyle McMartin , Usama Arif , kernel-team@meta.com, linux-arm-kernel@lists.infradead.org, iommu@lists.linux.dev, linux-tegra@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v6 1/2] iommu/arm-smmu-v3: Add a cmdq_max_n_shift module parameter Message-ID: References: <20260909095228.2174031-1-kas@kernel.org> <20260909095228.2174031-2-kas@kernel.org> <179018301689.3334538.1783583175230817305.b4-review@b4> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <179018301689.3334538.1783583175230817305.b4-review@b4> X-BeenThere: linux-arm-kernel@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-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, Sep 23, 2026 at 02:03:36PM -0300, Jason Gunthorpe wrote: > > [ ... 34 lines skipped ... ] > > @@ -40,6 +40,11 @@ module_param(disable_msipolling, bool, 0444); > > MODULE_PARM_DESC(disable_msipolling, > > "Disable MSI-based polling for CMD_SYNC completion."); > > > > +static unsigned int cmdq_max_n_shift; > > +module_param(cmdq_max_n_shift, uint, 0444); > > +MODULE_PARM_DESC(cmdq_max_n_shift, > > + "Cap on the command queue depth, as log2 of the number of entries. Zero means the hardware maximum; the queue never shrinks below one page."); > > The patch looks ok > > Reviewed-by: Jason Gunthorpe > > But I'd rather use lg2 as name, especially user visible, instead of > n_shift. "shift" is a word for bitwise stuff, this is a 2**N log2 > encoded value. This name has changed twice already. v5 took the value in entries. Nicolin asked for a log2 value and named it after max_n_shift, which is what the driver calls this quantity everywhere else. I would rather not rename it a third time without input from the maintainer. Will, this is the user-visible name. Do you have a preference here? Unless you want it changed I will leave v6 as it is. -- Kiryl Shutsemau / Kirill A. Shutemov