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-rw-r--r--ipc/shm.c148
1 files changed, 34 insertions, 114 deletions
diff --git a/ipc/shm.c b/ipc/shm.c
index b7224f330..6aaeb0084 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -24,7 +24,8 @@ 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 pte_t shm_swap_in(struct vm_area_struct *, unsigned long, unsigned long);
+static unsigned long shm_nopage(struct vm_area_struct *, unsigned long, int);
+static int shm_swapout(struct vm_area_struct *, struct page *);
static int shm_tot = 0; /* total number of shared memory pages */
static int shm_rss = 0; /* number of shared memory pages that are in memory */
@@ -364,10 +365,10 @@ static struct vm_operations_struct shm_vm_ops = {
NULL, /* protect */
NULL, /* sync */
NULL, /* advise */
- NULL, /* nopage (done with swapin) */
+ shm_nopage, /* nopage */
NULL, /* wppage */
- NULL, /* swapout (hardcoded right now) */
- shm_swap_in /* swapin */
+ shm_swapout, /* swapout */
+ NULL /* swapin */
};
/* Insert shmd into the list shp->attaches */
@@ -393,11 +394,7 @@ static inline void remove_attach (struct shmid_kernel * shp, struct vm_area_stru
*/
static int shm_map (struct vm_area_struct *shmd)
{
- pgd_t *page_dir;
- pmd_t *page_middle;
- pte_t *page_table;
- unsigned long tmp, shm_sgn;
- int error;
+ unsigned long tmp;
/* clear old mappings */
do_munmap(shmd->vm_start, shmd->vm_end - shmd->vm_start);
@@ -411,30 +408,7 @@ static int shm_map (struct vm_area_struct *shmd)
insert_vm_struct(current->mm, shmd);
merge_segments(current->mm, shmd->vm_start, shmd->vm_end);
- /* map page range */
- error = 0;
- shm_sgn = shmd->vm_pte +
- SWP_ENTRY(0, (shmd->vm_offset >> PAGE_SHIFT) << SHM_IDX_SHIFT);
- flush_cache_range(shmd->vm_mm, shmd->vm_start, shmd->vm_end);
- for (tmp = shmd->vm_start;
- tmp < shmd->vm_end;
- tmp += PAGE_SIZE, shm_sgn += SWP_ENTRY(0, 1 << SHM_IDX_SHIFT))
- {
- page_dir = pgd_offset(shmd->vm_mm,tmp);
- page_middle = pmd_alloc(page_dir,tmp);
- if (!page_middle) {
- error = -ENOMEM;
- break;
- }
- page_table = pte_alloc(page_middle,tmp);
- if (!page_table) {
- error = -ENOMEM;
- break;
- }
- set_pte(page_table, __pte(shm_sgn));
- }
- flush_tlb_range(shmd->vm_mm, shmd->vm_start, shmd->vm_end);
- return error;
+ return 0;
}
/*
@@ -615,53 +589,55 @@ asmlinkage int sys_shmdt (char *shmaddr)
}
/*
+ * Enter the shm page into the SHM data structures.
+ *
+ * The way "nopage" is done, we don't actually have to
+ * do anything here: nopage will have filled in the shm
+ * data structures already, and shm_swap_out() will just
+ * work off them..
+ */
+static int shm_swapout(struct vm_area_struct * vma, struct page * page)
+{
+ return 0;
+}
+
+/*
* page not present ... go through shm_pages
*/
-static pte_t shm_swap_in(struct vm_area_struct * shmd, unsigned long offset, unsigned long code)
+static unsigned long shm_nopage(struct vm_area_struct * shmd, unsigned long address, int no_share)
{
pte_t pte;
struct shmid_kernel *shp;
unsigned int id, idx;
- id = SWP_OFFSET(code) & SHM_ID_MASK;
+ id = SWP_OFFSET(shmd->vm_pte) & SHM_ID_MASK;
+ idx = (address - shmd->vm_start + shmd->vm_offset) >> PAGE_SHIFT;
+
#ifdef DEBUG_SHM
- if (id != (SWP_OFFSET(shmd->vm_pte) & SHM_ID_MASK)) {
- printk ("shm_swap_in: code id = %d and shmd id = %ld differ\n",
- id, SWP_OFFSET(shmd->vm_pte) & SHM_ID_MASK);
- return BAD_PAGE;
- }
if (id > max_shmid) {
- printk ("shm_swap_in: id=%d too big. proc mem corrupted\n", id);
- return BAD_PAGE;
+ printk ("shm_nopage: id=%d too big. proc mem corrupted\n", id);
+ return 0;
}
#endif
shp = shm_segs[id];
#ifdef DEBUG_SHM
if (shp == IPC_UNUSED || shp == IPC_NOID) {
- printk ("shm_swap_in: id=%d invalid. Race.\n", id);
- return BAD_PAGE;
- }
-#endif
- idx = (SWP_OFFSET(code) >> SHM_IDX_SHIFT) & SHM_IDX_MASK;
-#ifdef DEBUG_SHM
- if (idx != (offset >> PAGE_SHIFT)) {
- printk ("shm_swap_in: code idx = %u and shmd idx = %lu differ\n",
- idx, offset >> PAGE_SHIFT);
- return BAD_PAGE;
+ printk ("shm_nopage: id=%d invalid. Race.\n", id);
+ return 0;
}
if (idx >= shp->shm_npages) {
- printk ("shm_swap_in : too large page index. id=%d\n", id);
- return BAD_PAGE;
+ printk ("shm_nopage : too large page index. id=%d\n", id);
+ return 0;
}
#endif
pte = __pte(shp->shm_pages[idx]);
if (!pte_present(pte)) {
- unsigned long page = get_free_page(GFP_KERNEL);
+ unsigned long page = get_free_page(GFP_USER);
if (!page) {
oom(current);
- return BAD_PAGE;
+ return 0;
}
pte = __pte(shp->shm_pages[idx]);
if (pte_present(pte)) {
@@ -687,7 +663,7 @@ static pte_t shm_swap_in(struct vm_area_struct * shmd, unsigned long offset, uns
done: /* pte_val(pte) == shp->shm_pages[idx] */
current->min_flt++;
atomic_inc(&mem_map[MAP_NR(pte_page(pte))].count);
- return pte_modify(pte, shmd->vm_page_prot);
+ return pte_page(pte);
}
/*
@@ -700,7 +676,6 @@ int shm_swap (int prio, int gfp_mask)
{
pte_t page;
struct shmid_kernel *shp;
- struct vm_area_struct *shmd;
unsigned long swap_nr;
unsigned long id, idx;
int loop = 0;
@@ -716,10 +691,10 @@ int shm_swap (int prio, int gfp_mask)
next_id:
swap_idx = 0;
if (++swap_id > max_shmid) {
+ swap_id = 0;
if (loop)
goto failed;
loop = 1;
- swap_id = 0;
}
goto check_id;
}
@@ -742,61 +717,6 @@ int shm_swap (int prio, int gfp_mask)
swap_free (swap_nr);
return 0;
}
- if (shp->attaches)
- for (shmd = shp->attaches; ; ) {
- do {
- pgd_t *page_dir;
- pmd_t *page_middle;
- pte_t *page_table, pte;
- unsigned long tmp;
-
- if ((SWP_OFFSET(shmd->vm_pte) & SHM_ID_MASK) != id) {
- printk ("shm_swap: id=%ld does not match shmd->vm_pte.id=%ld\n",
- id, SWP_OFFSET(shmd->vm_pte) & SHM_ID_MASK);
- continue;
- }
- tmp = shmd->vm_start + (idx << PAGE_SHIFT) - shmd->vm_offset;
- if (!(tmp >= shmd->vm_start && tmp < shmd->vm_end))
- continue;
- page_dir = pgd_offset(shmd->vm_mm,tmp);
- if (pgd_none(*page_dir) || pgd_bad(*page_dir)) {
- printk("shm_swap: bad pgtbl! id=%ld start=%lx idx=%ld\n",
- id, shmd->vm_start, idx);
- pgd_clear(page_dir);
- continue;
- }
- page_middle = pmd_offset(page_dir,tmp);
- if (pmd_none(*page_middle) || pmd_bad(*page_middle)) {
- printk("shm_swap: bad pgmid! id=%ld start=%lx idx=%ld\n",
- id, shmd->vm_start, idx);
- pmd_clear(page_middle);
- continue;
- }
- page_table = pte_offset(page_middle,tmp);
- pte = *page_table;
- if (!pte_present(pte))
- continue;
- if (pte_young(pte)) {
- set_pte(page_table, pte_mkold(pte));
- continue;
- }
- if (pte_page(pte) != pte_page(page))
- printk("shm_swap_out: page and pte mismatch %lx %lx\n",
- pte_page(pte),pte_page(page));
- flush_cache_page(shmd, tmp);
- set_pte(page_table,
- __pte(shmd->vm_pte + SWP_ENTRY(0, idx << SHM_IDX_SHIFT)));
- atomic_dec(&mem_map[MAP_NR(pte_page(pte))].count);
- if (shmd->vm_mm->rss > 0)
- shmd->vm_mm->rss--;
- flush_tlb_page(shmd, tmp);
- /* continue looping through the linked list */
- } while (0);
- shmd = shmd->vm_next_share;
- if (!shmd)
- break;
- }
-
if (atomic_read(&mem_map[MAP_NR(pte_page(page))].count) != 1)
goto check_table;
shp->shm_pages[idx] = swap_nr;
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-09 22:38:11 +0000