From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.223.131]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A28E3206F37; Tue, 4 Feb 2025 08:57:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=195.135.223.131 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738659480; cv=none; b=o03QzZQHx8xP2y+NLaADaGxfxtB2g7hzTAfK1ieq/56cgvO5iofRXXOVh1X9uIjglWyCajQxHWtGt5/EZXrdk9TIJQEOPPF1t++yYG22IV4mecrx4Vmsjb2KcT7oXm7wC/UT09g0DeencZ0uONBp0xgYibCA1e2Nm0G48FRUb60= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738659480; c=relaxed/simple; bh=WmNrNpj+Bj06rH/pwHSM1a4lhx3h8jJhfqWsOyah+vo=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Ygj5wRHQXHtxMk3WqSYdPbcaXHFjdpFZtXP2GotzGr1uRLabVsy3TG9XBnT9RZGuten/+pJ9bcWPwUoLsTMIR6fupUICW7HCayQRSxctmGDZTbIA3UEa2S2rf3Xvx3tFI21o2/XAyxXCi7pdyBKFSKqQBNXsE9LRAHdWyW6uDsA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=suse.de; spf=pass smtp.mailfrom=suse.de; dkim=pass (1024-bit key) header.d=suse.de header.i=@suse.de header.b=RuEFR7Qz; dkim=permerror (0-bit key) header.d=suse.de header.i=@suse.de header.b=S6DneFJs; dkim=pass (1024-bit key) header.d=suse.de header.i=@suse.de header.b=iNdoeILj; dkim=permerror (0-bit key) header.d=suse.de header.i=@suse.de header.b=ad40dIOv; arc=none smtp.client-ip=195.135.223.131 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=suse.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=suse.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=suse.de header.i=@suse.de header.b="RuEFR7Qz"; dkim=permerror (0-bit key) header.d=suse.de header.i=@suse.de header.b="S6DneFJs"; dkim=pass (1024-bit key) header.d=suse.de header.i=@suse.de header.b="iNdoeILj"; dkim=permerror (0-bit key) header.d=suse.de header.i=@suse.de header.b="ad40dIOv" Received: from imap1.dmz-prg2.suse.org (imap1.dmz-prg2.suse.org [IPv6:2a07:de40:b281:104:10:150:64:97]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id E48081F38C; Tue, 4 Feb 2025 08:57:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1738659471; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:autocrypt:autocrypt; bh=0VvDvHhxmgNjkDWcgKUwYl0xE3yJzcwZtJvOY1zwhc0=; b=RuEFR7Qzn+NPsXHIH5qCplwT5yEzLUrUTdBXjSKMZKTqIgpwVkWty1RgRON8XCpfa+cdrV E8HTApER0XvacRDm8kyr1Kn5+xsBQrQbaGoG6xFgW8lCDqQ1N4mtAfrb23gnZd3gYaeykt 6AcUAyDgws7LxaNDkEh3gos8wXKQJOY= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1738659471; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:autocrypt:autocrypt; bh=0VvDvHhxmgNjkDWcgKUwYl0xE3yJzcwZtJvOY1zwhc0=; b=S6DneFJsfXNG7HP0F/vMovqnglSiOcpheUQ+Lu1stnP3Iumm+3XT3qT0JoaB+hPu3j2qD5 PUGJJfrYuIUfQWAA== Authentication-Results: smtp-out2.suse.de; dkim=pass header.d=suse.de header.s=susede2_rsa header.b=iNdoeILj; dkim=pass header.d=suse.de header.s=susede2_ed25519 header.b=ad40dIOv DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1738659470; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:autocrypt:autocrypt; bh=0VvDvHhxmgNjkDWcgKUwYl0xE3yJzcwZtJvOY1zwhc0=; b=iNdoeILjNA1+W+EOOBiuGmlrDKWnRljGyTBF29aRfmHKXlNDeH7HYqEez+sdTfTDdAFjHG uif4qxekqT2YYY1UsPqrFLnV7Id+WE5A//+7qVuenVxRa9a+77RBN4OgqYN6k+YtNoU6yi iASs3n2EALQ742/Bpl5DByznwFRKhXM= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1738659470; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:autocrypt:autocrypt; bh=0VvDvHhxmgNjkDWcgKUwYl0xE3yJzcwZtJvOY1zwhc0=; b=ad40dIOvPVJSEJZj3JXuUWB1HRz/BySiaTqsadPlvkc0C9DeTC5dgV3N0ynKC/uHurE6vX 49xS9jeGdRJOZuDg== Received: from imap1.dmz-prg2.suse.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by imap1.dmz-prg2.suse.org (Postfix) with ESMTPS id 858DA13795; Tue, 4 Feb 2025 08:57:50 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id 3HRUH47WoWeEdQAAD6G6ig (envelope-from ); Tue, 04 Feb 2025 08:57:50 +0000 Message-ID: Date: Tue, 4 Feb 2025 09:57:50 +0100 Precedence: bulk X-Mailing-List: linux-fbdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 3/3] fb_defio: do not use deprecated page->mapping, index fields To: Lorenzo Stoakes Cc: Andrew Morton , Jaya Kumar , Simona Vetter , Helge Deller , linux-fbdev@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Matthew Wilcox , David Hildenbrand , Kajtar Zsolt , Maira Canal References: <3542c5bb74d2487cf45d1d02ee5e73a05c4d279a.1738347308.git.lorenzo.stoakes@oracle.com> <168bdcc6-1035-4072-855b-afcfa2bf7e5d@lucifer.local> Content-Language: en-US From: Thomas Zimmermann Autocrypt: addr=tzimmermann@suse.de; keydata= xsBNBFs50uABCADEHPidWt974CaxBVbrIBwqcq/WURinJ3+2WlIrKWspiP83vfZKaXhFYsdg XH47fDVbPPj+d6tQrw5lPQCyqjwrCPYnq3WlIBnGPJ4/jreTL6V+qfKRDlGLWFjZcsrPJGE0 BeB5BbqP5erN1qylK9i3gPoQjXGhpBpQYwRrEyQyjuvk+Ev0K1Jc5tVDeJAuau3TGNgah4Yc hdHm3bkPjz9EErV85RwvImQ1dptvx6s7xzwXTgGAsaYZsL8WCwDaTuqFa1d1jjlaxg6+tZsB 9GluwvIhSezPgnEmimZDkGnZRRSFiGP8yjqTjjWuf0bSj5rUnTGiyLyRZRNGcXmu6hjlABEB AAHNJ1Rob21hcyBaaW1tZXJtYW5uIDx0emltbWVybWFubkBzdXNlLmRlPsLAjgQTAQgAOAIb AwULCQgHAgYVCgkICwIEFgIDAQIeAQIXgBYhBHIX+6yM6c9jRKFo5WgNwR1TC3ojBQJftODH AAoJEGgNwR1TC3ojx1wH/0hKGWugiqDgLNXLRD/4TfHBEKmxIrmfu9Z5t7vwUKfwhFL6hqvo lXPJJKQpQ2z8+X2vZm/slsLn7J1yjrOsoJhKABDi+3QWWSGkaGwRJAdPVVyJMfJRNNNIKwVb U6B1BkX2XDKDGffF4TxlOpSQzdtNI/9gleOoUA8+jy8knnDYzjBNOZqLG2FuTdicBXblz0Mf vg41gd9kCwYXDnD91rJU8tzylXv03E75NCaTxTM+FBXPmsAVYQ4GYhhgFt8S2UWMoaaABLDe 7l5FdnLdDEcbmd8uLU2CaG4W2cLrUaI4jz2XbkcPQkqTQ3EB67hYkjiEE6Zy3ggOitiQGcqp j//OwE0EWznS4AEIAMYmP4M/V+T5RY5at/g7rUdNsLhWv1APYrh9RQefODYHrNRHUE9eosYb T6XMryR9hT8XlGOYRwKWwiQBoWSDiTMo/Xi29jUnn4BXfI2px2DTXwc22LKtLAgTRjP+qbU6 3Y0xnQN29UGDbYgyyK51DW3H0If2a3JNsheAAK+Xc9baj0LGIc8T9uiEWHBnCH+RdhgATnWW GKdDegUR5BkDfDg5O/FISymJBHx2Dyoklv5g4BzkgqTqwmaYzsl8UxZKvbaxq0zbehDda8lv hFXodNFMAgTLJlLuDYOGLK2AwbrS3Sp0AEbkpdJBb44qVlGm5bApZouHeJ/+n+7r12+lqdsA EQEAAcLAdgQYAQgAIAIbDBYhBHIX+6yM6c9jRKFo5WgNwR1TC3ojBQJftOH6AAoJEGgNwR1T C3ojVSkIALpAPkIJPQoURPb1VWjh34l0HlglmYHvZszJWTXYwavHR8+k6Baa6H7ufXNQtThR yIxJrQLW6rV5lm7TjhffEhxVCn37+cg0zZ3j7zIsSS0rx/aMwi6VhFJA5hfn3T0TtrijKP4A SAQO9xD1Zk9/61JWk8OysuIh7MXkl0fxbRKWE93XeQBhIJHQfnc+YBLprdnxR446Sh8Wn/2D Ya8cavuWf2zrB6cZurs048xe0UbSW5AOSo4V9M0jzYI4nZqTmPxYyXbm30Kvmz0rYVRaitYJ 4kyYYMhuULvrJDMjZRvaNe52tkKAvMevcGdt38H4KSVXAylqyQOW5zvPc4/sq9c= In-Reply-To: <168bdcc6-1035-4072-855b-afcfa2bf7e5d@lucifer.local> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: E48081F38C X-Spam-Score: -3.01 X-Rspamd-Action: no action X-Spamd-Result: default: False [-3.01 / 50.00]; BAYES_HAM(-3.00)[100.00%]; SUSPICIOUS_RECIPS(1.50)[]; NEURAL_HAM_LONG(-1.00)[-1.000]; R_DKIM_ALLOW(-0.20)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; NEURAL_HAM_SHORT(-0.20)[-1.000]; MIME_GOOD(-0.10)[text/plain]; MX_GOOD(-0.01)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; FUZZY_BLOCKED(0.00)[rspamd.com]; ARC_NA(0.00)[]; DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; RCPT_COUNT_TWELVE(0.00)[13]; MIME_TRACE(0.00)[0:+]; FREEMAIL_ENVRCPT(0.00)[gmail.com,gmx.de]; FREEMAIL_CC(0.00)[linux-foundation.org,gmail.com,ffwll.ch,gmx.de,vger.kernel.org,lists.freedesktop.org,kvack.org,infradead.org,redhat.com,c64.rulez.org,igalia.com]; RCVD_TLS_ALL(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; FROM_EQ_ENVFROM(0.00)[]; FROM_HAS_DN(0.00)[]; TO_DN_SOME(0.00)[]; MID_RHS_MATCH_FROM(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; TAGGED_RCPT(0.00)[]; DKIM_TRACE(0.00)[suse.de:+]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.de:dkim,suse.de:mid,suse.de:email,imap1.dmz-prg2.suse.org:rdns,imap1.dmz-prg2.suse.org:helo] X-Rspamd-Server: rspamd1.dmz-prg2.suse.org X-Spam-Flag: NO X-Spam-Level: Hi Am 04.02.25 um 09:37 schrieb Lorenzo Stoakes: > On Tue, Feb 04, 2025 at 09:21:55AM +0100, Thomas Zimmermann wrote: >> Hi >> >> >> Am 31.01.25 um 19:28 schrieb Lorenzo Stoakes: >>> With the introduction of mapping_wrprotect_page() there is no need to use >>> folio_mkclean() in order to write-protect mappings of frame buffer pages, >>> and therefore no need to inappropriately set kernel-allocated page->index, >>> mapping fields to permit this operation. >>> >>> Instead, store the pointer to the page cache object for the mapped driver >>> in the fb_deferred_io object, and use the already stored page offset from >>> the pageref object to look up mappings in order to write-protect them. >>> >>> This is justified, as for the page objects to store a mapping pointer at >>> the point of assignment of pages, they must all reference the same >>> underlying address_space object. Since the life time of the pagerefs is >>> also the lifetime of the fb_deferred_io object, storing the pointer here >>> makes snese. >>> >>> This eliminates the need for all of the logic around setting and >>> maintaining page->index,mapping which we remove. >>> >>> This eliminates the use of folio_mkclean() entirely but otherwise should >>> have no functional change. >>> >>> Signed-off-by: Lorenzo Stoakes >>> Tested-by: Kajtar Zsolt >>> --- >>> drivers/video/fbdev/core/fb_defio.c | 38 +++++++++-------------------- >>> include/linux/fb.h | 1 + >>> 2 files changed, 12 insertions(+), 27 deletions(-) >>> >>> diff --git a/drivers/video/fbdev/core/fb_defio.c b/drivers/video/fbdev/core/fb_defio.c >>> index 65363df8e81b..b9bab27a8c0f 100644 >>> --- a/drivers/video/fbdev/core/fb_defio.c >>> +++ b/drivers/video/fbdev/core/fb_defio.c >>> @@ -69,14 +69,6 @@ static struct fb_deferred_io_pageref *fb_deferred_io_pageref_lookup(struct fb_in >>> return pageref; >>> } >>> -static void fb_deferred_io_pageref_clear(struct fb_deferred_io_pageref *pageref) >>> -{ >>> - struct page *page = pageref->page; >>> - >>> - if (page) >>> - page->mapping = NULL; >>> -} >>> - >>> static struct fb_deferred_io_pageref *fb_deferred_io_pageref_get(struct fb_info *info, >>> unsigned long offset, >>> struct page *page) >>> @@ -140,13 +132,10 @@ static vm_fault_t fb_deferred_io_fault(struct vm_fault *vmf) >>> if (!page) >>> return VM_FAULT_SIGBUS; >>> - if (vmf->vma->vm_file) >>> - page->mapping = vmf->vma->vm_file->f_mapping; >>> - else >>> + if (!vmf->vma->vm_file) >>> printk(KERN_ERR "no mapping available\n"); >> fb_err() here. > Ack, will fix on respin. > >>> - BUG_ON(!page->mapping); >>> - page->index = vmf->pgoff; /* for folio_mkclean() */ >>> + BUG_ON(!info->fbdefio->mapping); >>> vmf->page = page; >>> return 0; >>> @@ -194,9 +183,9 @@ static vm_fault_t fb_deferred_io_track_page(struct fb_info *info, unsigned long >>> /* >>> * We want the page to remain locked from ->page_mkwrite until >>> - * the PTE is marked dirty to avoid folio_mkclean() being called >>> - * before the PTE is updated, which would leave the page ignored >>> - * by defio. >>> + * the PTE is marked dirty to avoid mapping_wrprotect_page() >>> + * being called before the PTE is updated, which would leave >>> + * the page ignored by defio. >>> * Do this by locking the page here and informing the caller >>> * about it with VM_FAULT_LOCKED. >>> */ >>> @@ -274,14 +263,13 @@ static void fb_deferred_io_work(struct work_struct *work) >>> struct fb_deferred_io_pageref *pageref, *next; >>> struct fb_deferred_io *fbdefio = info->fbdefio; >>> - /* here we mkclean the pages, then do all deferred IO */ >>> + /* here we wrprotect the page's mappings, then do all deferred IO. */ >>> mutex_lock(&fbdefio->lock); >>> list_for_each_entry(pageref, &fbdefio->pagereflist, list) { >>> - struct folio *folio = page_folio(pageref->page); >>> + struct page *page = pageref->page; >>> + pgoff_t pgoff = pageref->offset >> PAGE_SHIFT; >>> - folio_lock(folio); >>> - folio_mkclean(folio); >>> - folio_unlock(folio); >>> + mapping_wrprotect_page(fbdefio->mapping, pgoff, 1, page); >>> } >>> /* driver's callback with pagereflist */ >>> @@ -337,6 +325,7 @@ void fb_deferred_io_open(struct fb_info *info, >>> { >>> struct fb_deferred_io *fbdefio = info->fbdefio; >>> + fbdefio->mapping = file->f_mapping; >> Does this still work if more than one program opens the file? > Yes, the mapping (address_space) pointer will remain the same across the > board. The way defio is implemented absolutely relies on this assumption. Great. With the fb_err() fixed, you can add Acked-by: Thomas Zimmermann to the patch. Best regards Thomas > >> Best regard >> Thomas >> >>> file->f_mapping->a_ops = &fb_deferred_io_aops; >>> fbdefio->open_count++; >>> } >>> @@ -344,13 +333,7 @@ EXPORT_SYMBOL_GPL(fb_deferred_io_open); >>> static void fb_deferred_io_lastclose(struct fb_info *info) >>> { >>> - unsigned long i; >>> - >>> flush_delayed_work(&info->deferred_work); >>> - >>> - /* clear out the mapping that we setup */ >>> - for (i = 0; i < info->npagerefs; ++i) >>> - fb_deferred_io_pageref_clear(&info->pagerefs[i]); >>> } >>> void fb_deferred_io_release(struct fb_info *info) >>> @@ -370,5 +353,6 @@ void fb_deferred_io_cleanup(struct fb_info *info) >>> kvfree(info->pagerefs); >>> mutex_destroy(&fbdefio->lock); >>> + fbdefio->mapping = NULL; >>> } >>> EXPORT_SYMBOL_GPL(fb_deferred_io_cleanup); >>> diff --git a/include/linux/fb.h b/include/linux/fb.h >>> index 5ba187e08cf7..cd653862ab99 100644 >>> --- a/include/linux/fb.h >>> +++ b/include/linux/fb.h >>> @@ -225,6 +225,7 @@ struct fb_deferred_io { >>> int open_count; /* number of opened files; protected by fb_info lock */ >>> struct mutex lock; /* mutex that protects the pageref list */ >>> struct list_head pagereflist; /* list of pagerefs for touched pages */ >>> + struct address_space *mapping; /* page cache object for fb device */ >>> /* callback */ >>> struct page *(*get_page)(struct fb_info *info, unsigned long offset); >>> void (*deferred_io)(struct fb_info *info, struct list_head *pagelist); >> -- >> -- >> Thomas Zimmermann >> Graphics Driver Developer >> SUSE Software Solutions Germany GmbH >> Frankenstrasse 146, 90461 Nuernberg, Germany >> GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman >> HRB 36809 (AG Nuernberg) >> -- -- Thomas Zimmermann Graphics Driver Developer SUSE Software Solutions Germany GmbH Frankenstrasse 146, 90461 Nuernberg, Germany GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman HRB 36809 (AG Nuernberg)