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3c1b7528d8
Commit "shmem: fix quota lock nesting in huge hole handling" was not so good: Smatch caught shmem_recalc_inode()'s shmem_inode_unacct_blocks() descending into quota_send_warning(): where blocking GFP_NOFS is used, yet shmem_recalc_inode() is called holding the shmem inode's info->lock. Yes, both __dquot_alloc_space() and __dquot_free_space() are commented "This operation can block, but only after everything is updated" - when calling flush_warnings() at the end - both its print_warning() and its quota_send_warning() may block. Rework shmem_recalc_inode() to take the shmem inode's info->lock inside, and drop it before calling shmem_inode_unacct_blocks(). And why were the spin_locks disabling interrupts? That was just a relic from when shmem_charge() and shmem_uncharge() were called while holding i_pages xa_lock: stop disabling interrupts for info->lock now. To help stop me from making the same mistake again, add a might_sleep() into shmem_inode_acct_block() and shmem_inode_unacct_blocks(); and those functions have grown, so let the compiler decide whether to inline them. Reported-by: Dan Carpenter <dan.carpenter@linaro.org> Closes: https://lore.kernel.org/linux-fsdevel/ffd7ca34-7f2a-44ee-b05d-b54d920ce076@moroto.mountain/ Signed-off-by: Hugh Dickins <hughd@google.com> Reviewed-by: Jan Kara <jack@suse.cz> Message-Id: <29f48045-2cb5-7db-ecf1-72462f1bef5@google.com> Signed-off-by: Christian Brauner <brauner@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
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Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
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https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.