From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 4450DC61DBE for ; Sat, 29 Aug 2026 10:35:21 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 515476B008A; Sat, 29 Aug 2026 06:35:20 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 4C69F6B008C; Sat, 29 Aug 2026 06:35:20 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3DD5F6B0092; Sat, 29 Aug 2026 06:35:20 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 14DE16B008A for ; Sat, 29 Aug 2026 06:35:20 -0400 (EDT) Received: from smtpin27.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 93C358069F for ; Sat, 29 Aug 2026 10:35:19 +0000 (UTC) X-FDA: 85153949958.27.0A6677E Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf30.hostedemail.com (Postfix) with ESMTP id E165480002 for ; Sat, 29 Aug 2026 10:35:17 +0000 (UTC) Authentication-Results: imf30.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=O4hQnDvs; spf=pass (imf30.hostedemail.com: domain of rppt@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=rppt@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1787999718; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=2cSRCs8wDnCpBsS5x9/4R2NQI4neq/3EffewAPnRfKA=; b=IO7LfYx1Nw/0pf7vhKf+sxPs7GzQlNwZSBQVsGOzTrsM3ZlAXRalQUB6IXBVN49OBlykuE RfeURVJvt7H9akbq7ZxXoinbPSNUkVgrFDruWaIKxqeJFs0bPanVOYE9QHd+1eIiX3inSH 3+fQPkfiA5DPBdoUZXISP00aI6hvhjo= ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1787999718; b=Ml62+bTvoPUiiZ3+vZbxutDoibPdR6GgKpHVbrLdIQLlYYdRfVALu7iHoieOl5bHTnPzDW AQNMJaQE09V0QMwT694XhX5Vkw1McK/vYbzmC2ltJVqErGT+SzspjsAblGvxhyxYyEXWZI 2VjEOVMcWKuKlJX1iESxywHZ3XyTYAU= ARC-Authentication-Results: i=1; imf30.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=O4hQnDvs; spf=pass (imf30.hostedemail.com: domain of rppt@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=rppt@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 0FAD043CDB; Sat, 29 Aug 2026 10:35:17 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1854E1F000E9; Sat, 29 Aug 2026 10:35:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1787999716; bh=2cSRCs8wDnCpBsS5x9/4R2NQI4neq/3EffewAPnRfKA=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=O4hQnDvsR3xz25zX0vx3nLmgtgXidRy0h4sWYehV2mXaWQF9J/8/dCttJ+E6EWeiL AU5vXmX8gEuh+eiBybVN36gcL9arMMcSOSmanqnA1H0jUHcst2QpkRCuZYvOQ1utna CmwIa3FMYIznrNaOU5idsntYbhRRO3HxdH82sL2QSmZq4KSQ//9h/0e1+1QzkyWNZ0 0rU3vqxq8xzjrVdcdZh5qOVfsw3iXccSIzOadiD6bqnoMbprP3lZK1UtNz4gXJHS5C 0O9KudEm0w62SpmKO8x56+dxacucnGq4B3gGwuAtRjfi6EA2/TmEU4oUb4c3BtwI86 LMFxBKkcdwmyA== Date: Sat, 29 Aug 2026 13:35:09 +0300 From: Mike Rapoport To: "Martin K. Petersen" Cc: Brian King , Hannes Reinecke , "James E.J. Bottomley" , Matthew Wilcox , Wen Xiong , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-scsi@vger.kernel.org, target-devel@vger.kernel.org, Hannes Reinecke , John Garry Subject: Re: [PATCH v2 0/4] scsi: replace __get_free_pages() with kmalloc() Message-ID: References: <20260704-b4-scsi-v2-0-7d2d21a810de@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260704-b4-scsi-v2-0-7d2d21a810de@kernel.org> X-Rspam-User: X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: E165480002 X-Stat-Signature: c3bgcor46y3hmmqih6gyiys58yd5zqk3 X-HE-Tag: 1787999717-580031 X-HE-Meta: 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 lQqldcHD 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Hi Martin, This seems to fall between the cracks. Do you want me to resend? On Sat, Jul 04, 2026 at 09:13:33AM +0300, Mike Rapoport (Microsoft) wrote: > This is a (small) part of larger work of replacing page allocator calls > with kmalloc. > > My initial intention a few month ago was to remove ugly casts [1], but then > willy pointed out that Linus objected to something like this [2] and it > looks like more than a decade old technical debt. > > Largely, anything that doesn't need struct page (or a memdesc in the > future) should just use kmalloc() or kvmalloc() to allocate memory. > kmalloc() guarantees alignment, physical contiguity and working > virt_to_phys() and beside nicer API that returns void * on alloc and > doesn't require to know the allocation size on free, kmalloc() provides > better debugging capabilities than page allocator. > > Another thing is that touching these allocation sites gives the reviewers > opportunity to see if a PAGE_SIZE buffer is actually needed or maybe > another size is appropriate. > > For larger allocations that don't need physically contiguous memory > kvmalloc() can be a better option that __get_free_pages() because under > memory pressure it's is easier to allocate several order-0 pages than a > physically contiguous chunk with the same number of pages. > > And last, but not least, removing needless calls to page allocator should > help with memdesc (aka project folio) conversion. There will be way less > places to audit to see if the user was actually using struct page. > > Also in git: > https://git.kernel.org/pub/scm/linux/kernel/git/rppt/linux.git gfp-to-kmalloc/scsi > > [1] https://lore.kernel.org/all/20251018093002.3660549-1-rppt@kernel.org/ > [2] https://lore.kernel.org/all/CA+55aFwp4iy4rtX2gE2WjBGFL=NxMVnoFeHqYa2j1dYOMMGqxg@mail.gmail.com/ > > --- > v2 changes: > * replace GFP_ATOMIC with GFP_NOIO in ipr driver > > v1: https://patch.msgid.link/20260630-b4-scsi-v1-0-494fb37ebe7b@kernel.org > > --- > Mike Rapoport (Microsoft) (4): > scsi: target: file: use kmalloc() to allocate temporary protection buffer > scsi: proc: use kmalloc() in proc writers > scsi: ipr: use kmalloc() to allocate IPR dump buffer memory > scsi: sym53c8xx_2: replace __get_free_pages() with kmalloc() > > drivers/scsi/ipr.c | 4 ++-- > drivers/scsi/scsi_devinfo.c | 5 +++-- > drivers/scsi/scsi_proc.c | 9 +++++---- > drivers/scsi/sym53c8xx_2/sym_hipd.h | 4 ++-- > drivers/target/target_core_file.c | 4 ++-- > 5 files changed, 14 insertions(+), 12 deletions(-) > --- > base-commit: dc59e4fea9d83f03bad6bddf3fa2e52491777482 > change-id: 20260611-b4-scsi-d0b0eb4895f4 > > -- > Sincerely yours, > Mike. > -- Sincerely yours, Mike.