From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-dl1-f43.google.com (mail-dl1-f43.google.com [74.125.82.43]) (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 97A6238C2BF for ; Sat, 23 May 2026 09:44:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=74.125.82.43 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779529463; cv=none; b=dV1PxwrPDMNweqAnk4gL0lVgpObSqDgc5uDieyqiEbZ9pFPVFPRM6D1jitq0DGIDXHxj9X4L7Yn4i22U6Wf+qFVozi1UJfTZT4ANvOgG0epvWTX9aEvQFGT7hDCYT/gBNnrMI0e6pbW0mo/Jlfu7kLHiwHe0Qo7P3mC8Q7lqH/s= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779529463; c=relaxed/simple; bh=8IuA4Maawk4JmdW1e3XdQBnbX3d39FsPRnY5vEwRHwA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=goTzDwq208Umxo9aGGDRBKFnPkeogwnK1kCiyJ1JTbiyTT2Cw+IEf9L1wZ+EJtyrYH09RayDqlVTt5mKEyf7/345FNDTKU2X0Mj5r74Nx5CBbkyRoA97UvmfxjMHuAvF+XNOot0ndyL/dWBV3Dq2NRIt61vMSct6xcW7HwNpeq8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=bvgpsEjh; arc=none smtp.client-ip=74.125.82.43 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="bvgpsEjh" Received: by mail-dl1-f43.google.com with SMTP id a92af1059eb24-135e7f4a295so2841138c88.0 for ; Sat, 23 May 2026 02:44:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1779529461; x=1780134261; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=fdYPrQ2V0SsFL9O2oIVedkPq9+Ea1ePouOP0UuVSLgA=; b=bvgpsEjhVR4o15s8rTpxVsKpo5hIHxpQcinL66XyGfZoL5n4yyxgoHmgwuNH6dWwPA g5BMmPge2j0R+Q01tdBNmqzYPY9gXtqSZPBcZvmo+sstSqtpsW+dfuZysvDl4aeNyDyd m0dX7IKlkIsguPaLtTCi8gD88wV3unc8hUYpTUuNLb4EW/Ef4LBSA/IzZBccWVghh0VK 6yS66CpEfV3eK/657IqrQqVmACxeruFZ667jhbWLOo7CWEb1Ovw6CUJ1gflVwRbNNyYm cjZQ1B2bsFAa5aGLjpwvVVisWRoQ0H3WYWW8nPHqTgGr0ONGmCq5u8Pphyni+Rw51348 ch/g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1779529461; x=1780134261; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=fdYPrQ2V0SsFL9O2oIVedkPq9+Ea1ePouOP0UuVSLgA=; b=DtIK01methYHGhtr1X7M+/cKDyrzVcXJl9oR8Jh6eBNFym9/VK5p81fqWB+HboCAbU gujBOvku9EyRFbM0xh6CtOpFd9bP9S/vRt/O3Tq9Fq0b6jHFRzDFwT1+vL8BRC1moB5h DKRMhdTPG5nRv6Xd1Sp4z0+TGe7GaBsHGkjR4HIAQEloR3tCLFhAU78LVV7pBar1RcK5 m1vc+O2YiBI1AGuRiNUR0XWlzsYKl62dNfm12M5fnZ2qPjDTMFpNAqUaCK66/8xONenC fh/ddmfTmuGdQ30YlTcB+40vvBA9HM0S8/fco9xdrlWQWszvjD0DCbNSvbz1z/0NIu+8 swew== X-Forwarded-Encrypted: i=1; AFNElJ/IFbJ/Wc1CDz7GTC84X22/f7sfmNGjWhx/5doj9vM+ercPj5A9oTnKYAqnPUb9k9q3WHkJgLgj0jYvTL8=@vger.kernel.org X-Gm-Message-State: AOJu0YzVYPQEdn6HAThRMfFGyT5T2Z/01R0FI9vi057ybSpb32Qj9kiD MrcnZgKgmn56TIim5k7bwoA0dfER9IT/IAiO5sIPOxQsebVeoM/fWWOj X-Gm-Gg: Acq92OFyPxnP1/CqhBK0Si5tMYh2bBd63wA2UzMpJ3mO/0y2wUvsJEfDjfEqBYIjoCc dosX727AlXQgWpkLrafHzrP3f2crmIQdOd2kLamId+iliy++Ztf4FsxeYedVAlTEDqmzUJpNI1E yusdA5N4XNKQ9komIsvO/qIKW2I8ZHdkQCqpRxykcRoXIob8ldlVOP+0G0R8G1U5I/7IRmzL27N faDzz60Imqj1QGDIgBF5O31G6JNl+fFvXQlMRolXNLrhTlr0r3S+xs3P0KMJddlJbYfF1TGDSkw U2XM6IpeTRNJwZqo6fYeyREfkm5KkFkug6eqjFBq2qO0T+A4v4lWB3IymkVIxSN9H94EtGIVkwv e2fhuffzBmz98JpnVNr7Rrk3jDXBs9FKQkXwuBNAb94jKlrnKoQLgaSfk2zo3e6oNwLXsYQW8k9 SkD9X0KvA/JbYsAcEzY9UT1fNQaM+NQamfkEa8E8i8qS62EJ2teXajJtUUQ2SlYzO9ubfepDMRX vrWVH8= X-Received: by 2002:a05:701b:4281:20b0:134:fc38:5d2f with SMTP id a92af1059eb24-136616f4055mr1707179c88.21.1779529460723; Sat, 23 May 2026 02:44:20 -0700 (PDT) Received: from AnisaLaptop.localdomain (c-73-170-217-179.hsd1.ca.comcast.net. [73.170.217.179]) by smtp.gmail.com with ESMTPSA id a92af1059eb24-1366a40305csm2376358c88.7.2026.05.23.02.44.19 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 23 May 2026 02:44:20 -0700 (PDT) From: Anisa Su X-Google-Original-From: Anisa Su To: linux-cxl@vger.kernel.org, linux-kernel@vger.kernel.org Cc: nvdimm@lists.linux.dev, Dan Williams , Jonathan Cameron , Davidlohr Bueso , Dave Jiang , Vishal Verma , Ira Weiny , Alison Schofield , John Groves , Gregory Price , Ira Weiny , Jonathan Cameron Subject: [PATCH v10 23/31] dax/bus: Factor out dev dax resize logic Date: Sat, 23 May 2026 02:43:17 -0700 Message-ID: <29393afa419cdffdd5d299cdc323262f5c20c036.1779528761.git.anisa.su@samsung.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Ira Weiny Dynamic Capacity (DC) DAX regions back their dax devices with per-extent resource children of the region, rather than carving from a single contiguous dax_region->res. Allocating space for a DC dax device — on initial uuid claim of its backing extents and on shrink-to-0 during destroy — needs the same allocator the static case uses, but pointed at a different parent resource. Factor the body of dev_dax_resize() into __dev_dax_resize(parent, ...) and add a dev_dax_resize_static() wrapper that passes dax_region->res for static (non-DC) regions. alloc_dev_dax_range() gains the same parent parameter so it can operate under either kind of parent. No functional change. Reviewed-by: Jonathan Cameron Reviewed-by: Dave Jiang Signed-off-by: Ira Weiny --- Changes: [anisa: reword to drop the options-considered discussion and "sparse" terminology; preserved in a later commit that realizes per-extent resource children] --- drivers/dax/bus.c | 131 ++++++++++++++++++++++++++++------------------ 1 file changed, 81 insertions(+), 50 deletions(-) diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c index 6368bdfdf93a..5c1b93890d30 100644 --- a/drivers/dax/bus.c +++ b/drivers/dax/bus.c @@ -1012,11 +1012,10 @@ static int devm_register_dax_mapping(struct dev_dax *dev_dax, int range_id) return 0; } -static int alloc_dev_dax_range(struct dev_dax *dev_dax, u64 start, - resource_size_t size, struct dax_resource *dax_resource) +static int alloc_dev_dax_range(struct resource *parent, struct dev_dax *dev_dax, + u64 start, resource_size_t size, + struct dax_resource *dax_resource) { - struct dax_region *dax_region = dev_dax->region; - struct resource *res = &dax_region->res; struct device *dev = &dev_dax->dev; struct dev_dax_range *ranges; unsigned long pgoff = 0; @@ -1034,14 +1033,14 @@ static int alloc_dev_dax_range(struct dev_dax *dev_dax, u64 start, return 0; } - alloc = __request_region(res, start, size, dev_name(dev), 0); + alloc = __request_region(parent, start, size, dev_name(dev), 0); if (!alloc) return -ENOMEM; ranges = krealloc(dev_dax->ranges, sizeof(*ranges) * (dev_dax->nr_range + 1), GFP_KERNEL); if (!ranges) { - __release_region(res, alloc->start, resource_size(alloc)); + __release_region(parent, alloc->start, resource_size(alloc)); return -ENOMEM; } @@ -1195,50 +1194,45 @@ static bool adjust_ok(struct dev_dax *dev_dax, struct resource *res) return true; } -static ssize_t dev_dax_resize(struct dax_region *dax_region, - struct dev_dax *dev_dax, resource_size_t size) +/** + * dev_dax_resize_static - Expand the device into the unused portion of the + * region. This may involve adjusting the end of an existing resource, or + * allocating a new resource. + * + * @parent: parent resource to allocate this range in + * @dev_dax: DAX device to be expanded + * @to_alloc: amount of space to alloc; must be <= space available in @parent + * + * Return the amount of space allocated or -ERRNO on failure + */ +static ssize_t dev_dax_resize_static(struct resource *parent, + struct dev_dax *dev_dax, + resource_size_t to_alloc) { - resource_size_t avail = dax_region_avail_size(dax_region), to_alloc; - resource_size_t dev_size = dev_dax_size(dev_dax); - struct resource *region_res = &dax_region->res; - struct device *dev = &dev_dax->dev; struct resource *res, *first; - resource_size_t alloc = 0; int rc; - if (dev->driver) - return -EBUSY; - if (size == dev_size) - return 0; - if (size > dev_size && size - dev_size > avail) - return -ENOSPC; - if (size < dev_size) - return dev_dax_shrink(dev_dax, size); - - to_alloc = size - dev_size; - if (dev_WARN_ONCE(dev, !alloc_is_aligned(dev_dax, to_alloc), - "resize of %pa misaligned\n", &to_alloc)) - return -ENXIO; - - /* - * Expand the device into the unused portion of the region. This - * may involve adjusting the end of an existing resource, or - * allocating a new resource. - */ -retry: - first = region_res->child; - if (!first) - return alloc_dev_dax_range(dev_dax, dax_region->res.start, to_alloc, NULL); + first = parent->child; + if (!first) { + rc = alloc_dev_dax_range(parent, dev_dax, + parent->start, to_alloc, NULL); + if (rc) + return rc; + return to_alloc; + } - rc = -ENOSPC; for (res = first; res; res = res->sibling) { struct resource *next = res->sibling; + resource_size_t alloc; /* space at the beginning of the region */ - if (res == first && res->start > dax_region->res.start) { - alloc = min(res->start - dax_region->res.start, to_alloc); - rc = alloc_dev_dax_range(dev_dax, dax_region->res.start, alloc, NULL); - break; + if (res == first && res->start > parent->start) { + alloc = min(res->start - parent->start, to_alloc); + rc = alloc_dev_dax_range(parent, dev_dax, + parent->start, alloc, NULL); + if (rc) + return rc; + return alloc; } alloc = 0; @@ -1247,21 +1241,56 @@ static ssize_t dev_dax_resize(struct dax_region *dax_region, alloc = min(next->start - (res->end + 1), to_alloc); /* space at the end of the region */ - if (!alloc && !next && res->end < region_res->end) - alloc = min(region_res->end - res->end, to_alloc); + if (!alloc && !next && res->end < parent->end) + alloc = min(parent->end - res->end, to_alloc); if (!alloc) continue; if (adjust_ok(dev_dax, res)) { rc = adjust_dev_dax_range(dev_dax, res, resource_size(res) + alloc); - break; + if (rc) + return rc; + return alloc; } - rc = alloc_dev_dax_range(dev_dax, res->end + 1, alloc, NULL); - break; + rc = alloc_dev_dax_range(parent, dev_dax, res->end + 1, alloc, NULL); + if (rc) + return rc; + return alloc; } - if (rc) - return rc; + + /* available was already calculated and should never be an issue */ + dev_WARN_ONCE(&dev_dax->dev, 1, "space not found?"); + return 0; +} + +static ssize_t dev_dax_resize(struct dax_region *dax_region, + struct dev_dax *dev_dax, resource_size_t size) +{ + resource_size_t avail = dax_region_avail_size(dax_region); + resource_size_t dev_size = dev_dax_size(dev_dax); + struct device *dev = &dev_dax->dev; + resource_size_t to_alloc; + resource_size_t alloc; + + if (dev->driver) + return -EBUSY; + if (size == dev_size) + return 0; + if (size > dev_size && size - dev_size > avail) + return -ENOSPC; + if (size < dev_size) + return dev_dax_shrink(dev_dax, size); + + to_alloc = size - dev_size; + if (dev_WARN_ONCE(dev, !alloc_is_aligned(dev_dax, to_alloc), + "resize of %pa misaligned\n", &to_alloc)) + return -ENXIO; + +retry: + alloc = dev_dax_resize_static(&dax_region->res, dev_dax, to_alloc); + if (alloc <= 0) + return alloc; to_alloc -= alloc; if (to_alloc) goto retry; @@ -1367,7 +1396,8 @@ static ssize_t mapping_store(struct device *dev, struct device_attribute *attr, to_alloc = range_len(&r); if (alloc_is_aligned(dev_dax, to_alloc)) - rc = alloc_dev_dax_range(dev_dax, r.start, to_alloc, NULL); + rc = alloc_dev_dax_range(&dax_region->res, dev_dax, r.start, + to_alloc, NULL); up_write(&dax_dev_rwsem); up_write(&dax_region_rwsem); @@ -1659,7 +1689,8 @@ static struct dev_dax *__devm_create_dev_dax(struct dev_dax_data *data) device_initialize(dev); dev_set_name(dev, "dax%d.%d", dax_region->id, dev_dax->id); - rc = alloc_dev_dax_range(dev_dax, dax_region->res.start, data->size, NULL); + rc = alloc_dev_dax_range(&dax_region->res, dev_dax, dax_region->res.start, + data->size, NULL); if (rc) goto err_range; -- 2.43.0