[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: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/arch/um/kernel/skas/uaccess.c b/arch/um/kernel/skas/uaccess.c
index 5992c32..8912cec 100644 (file)
--- a/arch/um/kernel/skas/uaccess.c
+++ b/arch/um/kernel/skas/uaccess.c
@@ -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;

diff --git a/include/asm-um/kmap_types.h b/include/asm-um/kmap_types.h
index 0b22ad7..6c03acd 100644 (file)
--- a/include/asm-um/kmap_types.h
+++ b/include/asm-um/kmap_types.h
@@ -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