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introduce memory_read_from_buffer()
This patch introduces memory_read_from_buffer(). The only difference between memory_read_from_buffer() and simple_read_from_buffer() is which address space the function copies to. simple_read_from_buffer copies to user space memory. memory_read_from_buffer copies to normal memory. Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Doug Warzecha <Douglas_Warzecha@dell.com> Cc: Zhang Rui <rui.zhang@intel.com> Cc: Matt Domsch <Matt_Domsch@dell.com> Cc: Abhay Salunke <Abhay_Salunke@dell.com> Cc: Greg Kroah-Hartman <gregkh@suse.de> Cc: Markus Rechberger <markus.rechberger@amd.com> Cc: Kay Sievers <kay.sievers@vrfy.org> Cc: Bob Moore <robert.moore@intel.com> Cc: Thomas Renninger <trenn@suse.de> Cc: Len Brown <lenb@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: "Antonino A. Daplas" <adaplas@pol.net> Cc: Krzysztof Helt <krzysztof.h1@poczta.fm> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Peter Oberparleiter <peter.oberparleiter@de.ibm.com> Cc: Michael Holzheu <holzheu@de.ibm.com> Cc: Brian King <brking@us.ibm.com> Cc: James E.J. Bottomley <James.Bottomley@HansenPartnership.com> Cc: Andrew Vasquez <linux-driver@qlogic.com> Cc: Seokmann Ju <seokmann.ju@qlogic.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
parent
3527fb326f
commit
93b071139a
18
fs/libfs.c
18
fs/libfs.c
@ -528,6 +528,23 @@ ssize_t simple_read_from_buffer(void __user *to, size_t count, loff_t *ppos,
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return count;
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}
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ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos,
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const void *from, size_t available)
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{
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loff_t pos = *ppos;
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if (pos < 0)
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return -EINVAL;
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if (pos >= available)
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return 0;
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if (count > available - pos)
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count = available - pos;
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memcpy(to, from + pos, count);
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*ppos = pos + count;
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return count;
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}
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/*
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* Transaction based IO.
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* The file expects a single write which triggers the transaction, and then
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@ -800,6 +817,7 @@ EXPORT_SYMBOL(simple_statfs);
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EXPORT_SYMBOL(simple_sync_file);
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EXPORT_SYMBOL(simple_unlink);
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EXPORT_SYMBOL(simple_read_from_buffer);
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EXPORT_SYMBOL(memory_read_from_buffer);
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EXPORT_SYMBOL(simple_transaction_get);
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EXPORT_SYMBOL(simple_transaction_read);
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EXPORT_SYMBOL(simple_transaction_release);
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@ -2000,7 +2000,10 @@ extern int simple_fill_super(struct super_block *, int, struct tree_descr *);
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extern int simple_pin_fs(struct file_system_type *, struct vfsmount **mount, int *count);
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extern void simple_release_fs(struct vfsmount **mount, int *count);
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extern ssize_t simple_read_from_buffer(void __user *, size_t, loff_t *, const void *, size_t);
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extern ssize_t simple_read_from_buffer(void __user *to, size_t count,
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loff_t *ppos, const void *from, size_t available);
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extern ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos,
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const void *from, size_t available);
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#ifdef CONFIG_MIGRATION
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extern int buffer_migrate_page(struct address_space *,
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