diff --git a/mm/swapfile.c b/mm/swapfile.c index 5e1e605ad9a1..78b49b0658ad 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -2138,7 +2138,16 @@ void swap_put_entries_direct(swp_entry_t entry, int nr) } #ifdef CONFIG_HIBERNATION -/* Allocate a slot for hibernation */ +/** + * swap_alloc_hibernation_slot() - Allocate a swap slot for hibernation. + * @type: swap device type index to allocate from. + * + * The caller must ensure the swap device is stable, either by pinning + * it (SWP_HIBERNATION) or by freezing user-space. + * + * Return: a valid swp_entry_t on success, or an empty entry (val == 0) + * on failure. + */ swp_entry_t swap_alloc_hibernation_slot(int type) { struct swap_info_struct *pcp_si, *si = swap_type_to_info(type); @@ -2149,46 +2158,42 @@ swp_entry_t swap_alloc_hibernation_slot(int type) if (!si) goto fail; - /* This is called for allocating swap entry, not cache */ - if (get_swap_device_info(si)) { - if (si->flags & SWP_WRITEOK) { - /* - * Try the local cluster first if it matches the device. If - * not, try grab a new cluster and override local cluster. - */ - local_lock(&percpu_swap_cluster.lock); - pcp_si = this_cpu_read(percpu_swap_cluster.si[0]); - pcp_offset = this_cpu_read(percpu_swap_cluster.offset[0]); - if (pcp_si == si && pcp_offset) { - ci = swap_cluster_lock(si, pcp_offset); - if (cluster_is_usable(ci, 0)) - offset = alloc_swap_scan_cluster(si, ci, NULL, pcp_offset); - else - swap_cluster_unlock(ci); - } - if (!offset) - offset = cluster_alloc_swap_entry(si, NULL); - local_unlock(&percpu_swap_cluster.lock); - if (offset) - entry = swp_entry(si->type, offset); - } - put_swap_device(si); + /* + * Try the local cluster first if it matches the device. If + * not, try grab a new cluster and override local cluster. + */ + local_lock(&percpu_swap_cluster.lock); + pcp_si = this_cpu_read(percpu_swap_cluster.si[0]); + pcp_offset = this_cpu_read(percpu_swap_cluster.offset[0]); + if (pcp_si == si && pcp_offset) { + ci = swap_cluster_lock(si, pcp_offset); + if (cluster_is_usable(ci, 0)) + offset = alloc_swap_scan_cluster(si, ci, NULL, pcp_offset); + else + swap_cluster_unlock(ci); } + if (!offset) + offset = cluster_alloc_swap_entry(si, NULL); + local_unlock(&percpu_swap_cluster.lock); + if (offset) + entry = swp_entry(si->type, offset); + fail: return entry; } -/* Free a slot allocated by swap_alloc_hibernation_slot */ +/** + * swap_free_hibernation_slot() - Free a swap slot allocated for hibernation. + * @entry: swap entry to free. + * + * The caller must ensure the swap device is stable. + */ void swap_free_hibernation_slot(swp_entry_t entry) { - struct swap_info_struct *si; + struct swap_info_struct *si = __swap_entry_to_info(entry); struct swap_cluster_info *ci; pgoff_t offset = swp_offset(entry); - si = get_swap_device(entry); - if (WARN_ON(!si)) - return; - ci = swap_cluster_lock(si, offset); __swap_cluster_put_entry(ci, offset % SWAPFILE_CLUSTER); __swap_cluster_free_entries(si, ci, offset % SWAPFILE_CLUSTER, 1); @@ -2196,7 +2201,6 @@ void swap_free_hibernation_slot(swp_entry_t entry) /* In theory readahead might add it to the swap cache by accident */ __try_to_reclaim_swap(si, offset, TTRS_ANYWAY); - put_swap_device(si); } static int __find_hibernation_swap_type(dev_t device, sector_t offset)