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Commit 47e5243a authored by Paolo 'Blaisorblade' Giarrusso's avatar Paolo 'Blaisorblade' Giarrusso Committed by Linus Torvalds
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[PATCH] uml: make copy_*_user atomic 



Make __copy_*_user_inatomic really atomic to avoid "Sleeping function called in
atomic context" warnings, especially from futex code.

This is made by adding another kmap_atomic slot and making copy_*_user_skas
use kmap_atomic; also copy_*_user() becomes atomic, but that's true and is not
a problem for i386 (and we can always add might_sleep there as done
elsewhere).  For TT mode kmap is not used, so there's no need for this.

I've had to use another slot since both KM_USER0 and KM_USER1 are used
elsewhere and could cause conflicts.  Till now we reused the kmap_atomic slot
list from the subarch, but that's not needed as that list must contain the
common ones (used by generic code) + the ones used in architecture specific
code (and Uml till now used none); so I've taken the i386 one after comparing
it with ones from other archs, and added KM_UML_USERCOPY.

Signed-off-by: default avatarPaolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 8ec4d41f

arch/um/kernel/skas/uaccess.c

+9 −6
Original line number Diff line number Diff line
@@ -8,6 +8,7 @@ 
#include "linux/kernel.h"

#include "linux/string.h"

#include "linux/fs.h"

#include "linux/hardirq.h"

#include "linux/highmem.h"

#include "asm/page.h"

#include "asm/pgtable.h"
@@ -38,7 +39,7 @@ static unsigned long maybe_map(unsigned long virt, int is_write) 
	return((unsigned long) phys);

}



static int do_op(unsigned long addr, int len, int is_write,

static int do_op_one_page(unsigned long addr, int len, int is_write,

		 int (*op)(unsigned long addr, int len, void *arg), void *arg)

{

	struct page *page;
@@ -49,9 +50,11 @@ static int do_op(unsigned long addr, int len, int is_write, 
		return(-1);



	page = phys_to_page(addr);

	addr = (unsigned long) kmap(page) + (addr & ~PAGE_MASK);

	addr = (unsigned long) kmap_atomic(page, KM_UML_USERCOPY) + (addr & ~PAGE_MASK);



	n = (*op)(addr, len, arg);

	kunmap(page);



	kunmap_atomic(page, KM_UML_USERCOPY);



	return(n);

}
@@ -77,7 +80,7 @@ static void do_buffer_op(void *jmpbuf, void *arg_ptr) 
	remain = len;



	current->thread.fault_catcher = jmpbuf;

	n = do_op(addr, size, is_write, op, arg);

	n = do_op_one_page(addr, size, is_write, op, arg);

	if(n != 0){

		*res = (n < 0 ? remain : 0);

		goto out;
@@ -91,7 +94,7 @@ static void do_buffer_op(void *jmpbuf, void *arg_ptr) 
	}



	while(addr < ((addr + remain) & PAGE_MASK)){

		n = do_op(addr, PAGE_SIZE, is_write, op, arg);

		n = do_op_one_page(addr, PAGE_SIZE, is_write, op, arg);

		if(n != 0){

			*res = (n < 0 ? remain : 0);

			goto out;
@@ -105,7 +108,7 @@ static void do_buffer_op(void *jmpbuf, void *arg_ptr) 
		goto out;

	}



	n = do_op(addr, remain, is_write, op, arg);

	n = do_op_one_page(addr, remain, is_write, op, arg);

	if(n != 0)

		*res = (n < 0 ? remain : 0);

	else *res = 0;

include/asm-um/kmap_types.h

+19 −1
Original line number Diff line number Diff line
@@ -6,6 +6,24 @@ 
#ifndef __UM_KMAP_TYPES_H

#define __UM_KMAP_TYPES_H



#include "asm/arch/kmap_types.h"

/* No more #include "asm/arch/kmap_types.h" ! */



enum km_type {

	KM_BOUNCE_READ,

	KM_SKB_SUNRPC_DATA,

	KM_SKB_DATA_SOFTIRQ,

	KM_USER0,

	KM_USER1,

	KM_UML_USERCOPY,	/* UML specific, for copy_*_user - used in do_op_one_page */

	KM_BIO_SRC_IRQ,

	KM_BIO_DST_IRQ,

	KM_PTE0,

	KM_PTE1,

	KM_IRQ0,

	KM_IRQ1,

	KM_SOFTIRQ0,

	KM_SOFTIRQ1,

	KM_TYPE_NR

};



#endif