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-rw-r--r--ipc/shm.c166
1 files changed, 73 insertions, 93 deletions
diff --git a/ipc/shm.c b/ipc/shm.c
index ca9275af1..653634ca8 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -1,13 +1,14 @@
/*
* linux/ipc/shm.c
* Copyright (C) 1992, 1993 Krishna Balasubramanian
- * Many improvements/fixes by Bruno Haible.
+ * Many improvements/fixes by Bruno Haible.
* Replaced `struct shm_desc' by `struct vm_area_struct', July 1994.
* Fixed the shm swap deallocation (shm_unuse()), August 1998 Andrea Arcangeli.
*
* /proc/sysvipc/shm support (c) 1999 Dragos Acostachioaie <dragos@iname.com>
* BIGMEM support, Andrea Arcangeli <andrea@suse.de>
* SMP thread shm, Jean-Luc Boyard <jean-luc.boyard@siemens.fr>
+ * HIGHMEM support, Ingo Molnar <mingo@redhat.com>
*/
#include <linux/config.h>
@@ -19,20 +20,19 @@
#include <linux/vmalloc.h>
#include <linux/pagemap.h>
#include <linux/proc_fs.h>
-#include <linux/bigmem.h>
+#include <linux/highmem.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
extern int ipcperms (struct ipc_perm *ipcp, short shmflg);
-extern unsigned long get_swap_page (void);
static int findkey (key_t key);
static int newseg (key_t key, int shmflg, int size);
static int shm_map (struct vm_area_struct *shmd);
static void killseg (int id);
static void shm_open (struct vm_area_struct *shmd);
static void shm_close (struct vm_area_struct *shmd);
-static unsigned long shm_nopage(struct vm_area_struct *, unsigned long, int);
+static struct page * shm_nopage(struct vm_area_struct *, unsigned long, int);
static int shm_swapout(struct vm_area_struct *, struct page *);
#ifdef CONFIG_PROC_FS
static int sysvipc_shm_read_proc(char *buffer, char **start, off_t offset, int length, int *eof, void *data);
@@ -108,7 +108,7 @@ static int newseg (key_t key, int shmflg, int size)
{
struct shmid_kernel *shp;
int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT;
- int id, i;
+ int id;
if (size < SHMMIN)
return -EINVAL;
@@ -131,7 +131,7 @@ found:
return -ENOMEM;
}
lock_kernel();
- shp->shm_pages = (ulong *) vmalloc (numpages*sizeof(ulong));
+ shp->shm_pages = (pte_t *) vmalloc (numpages*sizeof(pte_t));
unlock_kernel();
if (!shp->shm_pages) {
kfree(shp);
@@ -141,7 +141,8 @@ found:
return -ENOMEM;
}
- for (i = 0; i < numpages; shp->shm_pages[i++] = 0);
+ memset(shp->shm_pages, 0, numpages*sizeof(pte_t));
+
shp->u.shm_perm.key = key;
shp->u.shm_perm.mode = (shmflg & S_IRWXUGO);
shp->u.shm_perm.cuid = shp->u.shm_perm.uid = current->euid;
@@ -214,33 +215,29 @@ static void killseg (int id)
int rss, swp;
shp = shm_segs[id];
- if (shp == IPC_NOID || shp == IPC_UNUSED) {
- printk ("shm nono: killseg called on unused seg id=%d\n", id);
- return;
- }
+ if (shp == IPC_NOID || shp == IPC_UNUSED)
+ BUG();
shp->u.shm_perm.seq++; /* for shmat */
shm_seq = (shm_seq+1) % ((unsigned)(1<<31)/SHMMNI); /* increment, but avoid overflow */
shm_segs[id] = (struct shmid_kernel *) IPC_UNUSED;
used_segs--;
if (id == max_shmid)
while (max_shmid && (shm_segs[--max_shmid] == IPC_UNUSED));
- if (!shp->shm_pages) {
- printk ("shm nono: killseg shp->pages=NULL. id=%d\n", id);
- return;
- }
+ if (!shp->shm_pages)
+ BUG();
spin_unlock(&shm_lock);
numpages = shp->shm_npages;
for (i = 0, rss = 0, swp = 0; i < numpages ; i++) {
pte_t pte;
- pte = __pte(shp->shm_pages[i]);
+ pte = shp->shm_pages[i];
if (pte_none(pte))
continue;
if (pte_present(pte)) {
- free_page (pte_page(pte));
+ __free_page (pte_page(pte));
rss++;
} else {
lock_kernel();
- swap_free(pte_val(pte));
+ swap_free(pte);
unlock_kernel();
swp++;
}
@@ -462,8 +459,10 @@ static int shm_map (struct vm_area_struct *shmd)
> (unsigned long) current->rlim[RLIMIT_AS].rlim_cur)
return -ENOMEM;
current->mm->total_vm += tmp >> PAGE_SHIFT;
+ vmlist_modify_lock(current->mm);
insert_vm_struct(current->mm, shmd);
merge_segments(current->mm, shmd->vm_start, shmd->vm_end);
+ vmlist_modify_unlock(current->mm);
return 0;
}
@@ -482,16 +481,12 @@ asmlinkage long sys_shmat (int shmid, char *shmaddr, int shmflg, ulong *raddr)
down(&current->mm->mmap_sem);
spin_lock(&shm_lock);
- if (shmid < 0) {
- /* printk("shmat() -> EINVAL because shmid = %d < 0\n",shmid); */
+ if (shmid < 0)
goto out;
- }
shp = shm_segs[id = (unsigned int) shmid % SHMMNI];
- if (shp == IPC_UNUSED || shp == IPC_NOID) {
- /* printk("shmat() -> EINVAL because shmid = %d is invalid\n",shmid); */
+ if (shp == IPC_UNUSED || shp == IPC_NOID)
goto out;
- }
if (!(addr = (ulong) shmaddr)) {
if (shmflg & SHM_REMAP)
@@ -524,16 +519,9 @@ asmlinkage long sys_shmat (int shmid, char *shmaddr, int shmflg, ulong *raddr)
*/
if (addr < current->mm->start_stack &&
addr > current->mm->start_stack - PAGE_SIZE*(shp->shm_npages + 4))
- {
- /* printk("shmat() -> EINVAL because segment intersects stack\n"); */
goto out;
- }
- if (!(shmflg & SHM_REMAP))
- if ((shmd = find_vma_intersection(current->mm, addr, addr + shp->u.shm_segsz))) {
- /* printk("shmat() -> EINVAL because the interval [0x%lx,0x%lx) intersects an already mapped interval [0x%lx,0x%lx).\n",
- addr, addr + shp->shm_segsz, shmd->vm_start, shmd->vm_end); */
- goto out;
- }
+ if (!(shmflg & SHM_REMAP) && find_vma_intersection(current->mm, addr, addr + shp->u.shm_segsz))
+ goto out;
err = -EACCES;
if (ipcperms(&shp->u.shm_perm, shmflg & SHM_RDONLY ? S_IRUGO : S_IRUGO|S_IWUGO))
@@ -566,7 +554,7 @@ asmlinkage long sys_shmat (int shmid, char *shmaddr, int shmflg, ulong *raddr)
shmd->vm_offset = 0;
shmd->vm_ops = &shm_vm_ops;
- shp->u.shm_nattch++; /* prevent destruction */
+ shp->u.shm_nattch++; /* prevent destruction */
spin_unlock(&shm_lock);
err = shm_map (shmd);
spin_lock(&shm_lock);
@@ -666,86 +654,76 @@ static int shm_swapout(struct vm_area_struct * vma, struct page * page)
/*
* page not present ... go through shm_pages
*/
-static unsigned long shm_nopage(struct vm_area_struct * shmd, unsigned long address, int no_share)
+static struct page * shm_nopage(struct vm_area_struct * shmd, unsigned long address, int no_share)
{
pte_t pte;
struct shmid_kernel *shp;
unsigned int idx;
- unsigned long page;
- struct page * page_map;
+ struct page * page;
shp = *(struct shmid_kernel **) shmd->vm_private_data;
idx = (address - shmd->vm_start + shmd->vm_offset) >> PAGE_SHIFT;
-#ifdef DEBUG_SHM
- if (shp == IPC_UNUSED || shp == IPC_NOID) {
- printk ("shm_nopage: id=%d invalid. Race.\n", id);
- return 0;
- }
- if (idx >= shp->shm_npages) {
- printk ("shm_nopage : too large page index. id=%d\n", id);
- return 0;
- }
-#endif
-
spin_lock(&shm_lock);
- again:
- pte = __pte(shp->shm_pages[idx]);
+again:
+ pte = shp->shm_pages[idx];
if (!pte_present(pte)) {
if (pte_none(pte)) {
spin_unlock(&shm_lock);
- page = __get_free_page(GFP_BIGUSER);
+ page = get_free_highpage(GFP_HIGHUSER);
if (!page)
goto oom;
- clear_bigpage(page);
+ clear_highpage(page);
spin_lock(&shm_lock);
- if (pte_val(pte) != shp->shm_pages[idx])
+ if (pte_val(pte) != pte_val(shp->shm_pages[idx]))
goto changed;
} else {
- unsigned long entry = pte_val(pte);
+ pte_t entry = pte;
spin_unlock(&shm_lock);
- page_map = lookup_swap_cache(entry);
- if (!page_map) {
+ BUG();
+ page = lookup_swap_cache(entry);
+ if (!page) {
lock_kernel();
swapin_readahead(entry);
- page_map = read_swap_cache(entry);
+ page = read_swap_cache(entry);
unlock_kernel();
- if (!page_map)
+ if (!page)
goto oom;
}
- delete_from_swap_cache(page_map);
- page_map = replace_with_bigmem(page_map);
- page = page_address(page_map);
+ delete_from_swap_cache(page);
+ page = replace_with_highmem(page);
lock_kernel();
swap_free(entry);
unlock_kernel();
spin_lock(&shm_lock);
shm_swp--;
- pte = __pte(shp->shm_pages[idx]);
+ pte = shp->shm_pages[idx];
if (pte_present(pte))
goto present;
}
shm_rss++;
pte = pte_mkdirty(mk_pte(page, PAGE_SHARED));
- shp->shm_pages[idx] = pte_val(pte);
+ shp->shm_pages[idx] = pte;
} else
--current->maj_flt; /* was incremented in do_no_page */
-done: /* pte_val(pte) == shp->shm_pages[idx] */
- get_page(mem_map + MAP_NR(pte_page(pte)));
+done:
+ /* pte_val(pte) == shp->shm_pages[idx] */
+ get_page(pte_page(pte));
spin_unlock(&shm_lock);
current->min_flt++;
return pte_page(pte);
changed:
- free_page(page);
+ __free_page(page);
goto again;
present:
- free_page(page);
+ if (page)
+ free_page_and_swap_cache(page);
goto done;
oom:
- return -1;
+ return (struct page *)(-1);
}
/*
@@ -758,7 +736,7 @@ int shm_swap (int prio, int gfp_mask)
{
pte_t page;
struct shmid_kernel *shp;
- unsigned long swap_nr;
+ pte_t swap_entry;
unsigned long id, idx;
int loop = 0;
int counter;
@@ -766,7 +744,7 @@ int shm_swap (int prio, int gfp_mask)
counter = shm_rss >> prio;
lock_kernel();
- if (!counter || !(swap_nr = get_swap_page())) {
+ if (!counter || !pte_val(swap_entry = get_swap_page())) {
unlock_kernel();
return 0;
}
@@ -793,36 +771,37 @@ int shm_swap (int prio, int gfp_mask)
if (idx >= shp->shm_npages)
goto next_id;
- page = __pte(shp->shm_pages[idx]);
+ page = shp->shm_pages[idx];
if (!pte_present(page))
goto check_table;
- page_map = &mem_map[MAP_NR(pte_page(page))];
+ page_map = pte_page(page);
if ((gfp_mask & __GFP_DMA) && !PageDMA(page_map))
goto check_table;
- if (!(gfp_mask & __GFP_BIGMEM) && PageBIGMEM(page_map))
+ if (!(gfp_mask & __GFP_HIGHMEM) && PageHighMem(page_map))
goto check_table;
swap_attempts++;
if (--counter < 0) { /* failed */
- failed:
+failed:
spin_unlock(&shm_lock);
lock_kernel();
- swap_free (swap_nr);
+ swap_free(swap_entry);
unlock_kernel();
return 0;
}
- if (page_count(mem_map + MAP_NR(pte_page(page))) != 1)
+ if (page_count(page_map))
goto check_table;
- if (!(page_map = prepare_bigmem_swapout(page_map)))
+ if (!(page_map = prepare_highmem_swapout(page_map)))
goto check_table;
- shp->shm_pages[idx] = swap_nr;
+ shp->shm_pages[idx] = swap_entry;
swap_successes++;
shm_swp++;
shm_rss--;
spin_unlock(&shm_lock);
+
lock_kernel();
- swap_duplicate(swap_nr);
- add_to_swap_cache(page_map, swap_nr);
+ swap_duplicate(swap_entry);
+ add_to_swap_cache(page_map, swap_entry);
rw_swap_page(WRITE, page_map, 0);
unlock_kernel();
@@ -834,13 +813,13 @@ int shm_swap (int prio, int gfp_mask)
* Free the swap entry and set the new pte for the shm page.
*/
static void shm_unuse_page(struct shmid_kernel *shp, unsigned long idx,
- unsigned long page, unsigned long entry)
+ pte_t entry, struct page *page)
{
pte_t pte;
pte = pte_mkdirty(mk_pte(page, PAGE_SHARED));
- shp->shm_pages[idx] = pte_val(pte);
- get_page(mem_map + MAP_NR(page));
+ shp->shm_pages[idx] = pte;
+ get_page(page);
shm_rss++;
shm_swp--;
@@ -854,20 +833,21 @@ static void shm_unuse_page(struct shmid_kernel *shp, unsigned long idx,
/*
* unuse_shm() search for an eventually swapped out shm page.
*/
-void shm_unuse(unsigned long entry, unsigned long page)
+void shm_unuse(pte_t entry, struct page *page)
{
int i, n;
spin_lock(&shm_lock);
- for (i = 0; i < SHMMNI; i++)
- if (shm_segs[i] != IPC_UNUSED && shm_segs[i] != IPC_NOID)
- for (n = 0; n < shm_segs[i]->shm_npages; n++)
- if (shm_segs[i]->shm_pages[n] == entry)
- {
- shm_unuse_page(shm_segs[i], n,
- page, entry);
- return;
- }
+ for (i = 0; i < SHMMNI; i++) {
+ struct shmid_kernel *seg = shm_segs[i];
+ if ((seg == IPC_UNUSED) || (seg == IPC_NOID))
+ continue;
+ for (n = 0; n < seg->shm_npages; n++)
+ if (pte_val(seg->shm_pages[n]) == pte_val(entry)) {
+ shm_unuse_page(seg, n, entry, page);
+ return;
+ }
+ }
spin_unlock(&shm_lock);
}
generated by cgit v1.2.3 (git 2.25.1) at 2024-09-19 21:27:09 +0000