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Wysocki" , Danilo Krummrich , Andrew Morton , David Hildenbrand , Lorenzo Stoakes , Keith Busch , Jens Axboe , Christoph Hellwig , Sagi Grimberg , houtao1@huawei.com Subject: [PATCH 03/13] kernfs: add support for get_unmapped_area callback Date: Sat, 20 Dec 2025 12:04:36 +0800 Message-Id: <20251220040446.274991-4-houtao@huaweicloud.com> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20251220040446.274991-1-houtao@huaweicloud.com> References: <20251220040446.274991-1-houtao@huaweicloud.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CM-TRANSID:gCh0CgD3WPn5IkZpFwpFAw--.56015S7 X-Coremail-Antispam: 1UD129KBjvJXoWxArWDZr4ftw1DCry8urWrGrg_yoW5CrW8pF s5KryYqrWxJr92kr13JF95Zr1av3s7Ka42va4Ig3sYyw1jqFnxXr4Y9F98Gr1rX34rAw42 yanFgayYkw45JrUanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUPab4IE77IF4wAFF20E14v26rWj6s0DM7CY07I20VC2zVCF04k2 6cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M28IrcIa0xkI8VA2jI8067AKxVWUWw A2048vs2IY020Ec7CjxVAFwI0_Xr0E3s1l8cAvFVAK0II2c7xJM28CjxkF64kEwVA0rcxS w2x7M28EF7xvwVC0I7IYx2IY67AKxVW7JVWDJwA2z4x0Y4vE2Ix0cI8IcVCY1x0267AKxV W8Jr0_Cr1UM28EF7xvwVC2z280aVAFwI0_GcCE3s1l84ACjcxK6I8E87Iv6xkF7I0E14v2 6rxl6s0DM2AIxVAIcxkEcVAq07x20xvEncxIr21l5I8CrVACY4xI64kE6c02F40Ex7xfMc Ij6xIIjxv20xvE14v26r126r1DMcIj6I8E87Iv67AKxVW8Jr0_Cr1UMcvjeVCFs4IE7xkE bVWUJVW8JwACjcxG0xvY0x0EwIxGrwACI402YVCY1x02628vn2kIc2xKxwCY1x0262kKe7 AKxVW8ZVWrXwCF04k20xvY0x0EwIxGrwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02 F40E14v26r1j6r18MI8I3I0E7480Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_GFv_Wr ylIxkGc2Ij64vIr41lIxAIcVC0I7IYx2IY67AKxVWUJVWUCwCI42IY6xIIjxv20xvEc7Cj xVAFwI0_Cr0_Gr1UMIIF0xvE42xK8VAvwI8IcIk0rVWUJVWUCwCI42IY6I8E87Iv67AKxV WUJVW8JwCI42IY6I8E87Iv6xkF7I0E14v26r4j6r4UJbIYCTnIWIevJa73UjIFyTuYvjxU xQzVUUUUU X-CM-SenderInfo: xkrx3t3r6k3tpzhluzxrxghudrp/ X-Rspam-User: X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 749838000B X-Stat-Signature: 4q93xy3op9ku8d63oo4sjhiy7o4ag7fr X-HE-Tag: 1766204174-591968 X-HE-Meta: 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: From: Hou Tao kernfs has already support ->mmap callback, however it doesn't support ->get_unmapped_area callback to return PMD-aligned or PUD-aligned virtual address. The following patch will need it to support compound page for p2pdma device memory, therefore add the necessary support for it. When the ->get_unmapped_area callback is not defined in kernfs_ops or the callback returns -EOPNOTSUPP, kernfs_get_unmapped_area() will fallback to mm_get_unmapped_area(). Signed-off-by: Hou Tao --- fs/kernfs/file.c | 37 +++++++++++++++++++++++++++++++++++++ include/linux/kernfs.h | 3 +++ 2 files changed, 40 insertions(+) diff --git a/fs/kernfs/file.c b/fs/kernfs/file.c index 9adf36e6364b..9773b5734a2c 100644 --- a/fs/kernfs/file.c +++ b/fs/kernfs/file.c @@ -454,6 +454,39 @@ static const struct vm_operations_struct kernfs_vm_ops = { .access = kernfs_vma_access, }; +static unsigned long kernfs_get_unmapped_area(struct file *file, unsigned long uaddr, + unsigned long len, unsigned long pgoff, + unsigned long flags) +{ + struct kernfs_open_file *of = kernfs_of(file); + const struct kernfs_ops *ops; + long addr; + + if (!(of->kn->flags & KERNFS_HAS_MMAP)) + return -ENODEV; + + mutex_lock(&of->mutex); + + addr = -ENODEV; + if (!kernfs_get_active_of(of)) + goto out_unlock; + + ops = kernfs_ops(of->kn); + if (ops->get_unmapped_area) { + addr = ops->get_unmapped_area(of, uaddr, len, pgoff, flags); + if (!IS_ERR_VALUE(addr) || addr != -EOPNOTSUPP) + goto out_put; + } + addr = mm_get_unmapped_area(file, uaddr, len, pgoff, flags); + +out_put: + kernfs_put_active_of(of); +out_unlock: + mutex_unlock(&of->mutex); + + return addr; +} + static int kernfs_fop_mmap(struct file *file, struct vm_area_struct *vma) { struct kernfs_open_file *of = kernfs_of(file); @@ -1017,6 +1050,7 @@ const struct file_operations kernfs_file_fops = { .write_iter = kernfs_fop_write_iter, .llseek = kernfs_fop_llseek, .mmap = kernfs_fop_mmap, + .get_unmapped_area = kernfs_get_unmapped_area, .open = kernfs_fop_open, .release = kernfs_fop_release, .poll = kernfs_fop_poll, @@ -1052,6 +1086,9 @@ struct kernfs_node *__kernfs_create_file(struct kernfs_node *parent, unsigned flags; int rc; + if (ops->get_unmapped_area && !ops->mmap) + return ERR_PTR(-EINVAL); + flags = KERNFS_FILE; kn = kernfs_new_node(parent, name, (mode & S_IALLUGO) | S_IFREG, diff --git a/include/linux/kernfs.h b/include/linux/kernfs.h index b5a5f32fdfd1..9467b0a2b339 100644 --- a/include/linux/kernfs.h +++ b/include/linux/kernfs.h @@ -324,6 +324,9 @@ struct kernfs_ops { int (*mmap)(struct kernfs_open_file *of, struct vm_area_struct *vma); loff_t (*llseek)(struct kernfs_open_file *of, loff_t offset, int whence); + unsigned long (*get_unmapped_area)(struct kernfs_open_file *of, unsigned long uaddr, + unsigned long len, unsigned long pgoff, + unsigned long flags); }; /* -- 2.29.2