staging: zcache: crypto API support
This patch allow zcache to use the crypto API for page compression. It replaces the direct LZO compress/decompress calls with calls into the crypto compression API. The compressor to be used is specified in the kernel boot line with the zcache parameter like: zcache=lzo or zcache=deflate. If the specified compressor can't be loaded, zcache uses lzo as the default compressor. Signed-off-by: Seth Jennings <sjenning@linux.vnet.ibm.com> Acked-by: Dan Magenheimer <dan.magenheimer@oracle.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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@ -1,13 +1,12 @@
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config ZCACHE
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tristate "Dynamic compression of swap pages and clean pagecache pages"
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depends on CLEANCACHE || FRONTSWAP
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depends on (CLEANCACHE || FRONTSWAP) && CRYPTO
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select XVMALLOC
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select LZO_COMPRESS
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select LZO_DECOMPRESS
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select CRYPTO_LZO
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default n
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help
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Zcache doubles RAM efficiency while providing a significant
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performance boosts on many workloads. Zcache uses lzo1x
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performance boosts on many workloads. Zcache uses
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compression and an in-kernel implementation of transcendent
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memory to store clean page cache pages and swap in RAM,
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providing a noticeable reduction in disk I/O.
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@ -6,7 +6,8 @@
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*
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* Zcache provides an in-kernel "host implementation" for transcendent memory
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* and, thus indirectly, for cleancache and frontswap. Zcache includes two
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* page-accessible memory [1] interfaces, both utilizing lzo1x compression:
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* page-accessible memory [1] interfaces, both utilizing the crypto compression
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* API:
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* 1) "compression buddies" ("zbud") is used for ephemeral pages
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* 2) xvmalloc is used for persistent pages.
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* Xvmalloc (based on the TLSF allocator) has very low fragmentation
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@ -23,12 +24,13 @@
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#include <linux/cpu.h>
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#include <linux/highmem.h>
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#include <linux/list.h>
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#include <linux/lzo.h>
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#include <linux/slab.h>
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#include <linux/spinlock.h>
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#include <linux/types.h>
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#include <linux/atomic.h>
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#include <linux/math64.h>
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#include <linux/crypto.h>
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#include <linux/string.h>
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#include "tmem.h"
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#include "../zram/xvmalloc.h" /* if built in drivers/staging */
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@ -81,6 +83,38 @@ static inline bool is_local_client(struct zcache_client *cli)
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return cli == &zcache_host;
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}
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/* crypto API for zcache */
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#define ZCACHE_COMP_NAME_SZ CRYPTO_MAX_ALG_NAME
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static char zcache_comp_name[ZCACHE_COMP_NAME_SZ];
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static struct crypto_comp * __percpu *zcache_comp_pcpu_tfms;
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enum comp_op {
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ZCACHE_COMPOP_COMPRESS,
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ZCACHE_COMPOP_DECOMPRESS
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};
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static inline int zcache_comp_op(enum comp_op op,
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const u8 *src, unsigned int slen,
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u8 *dst, unsigned int *dlen)
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{
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struct crypto_comp *tfm;
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int ret;
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BUG_ON(!zcache_comp_pcpu_tfms);
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tfm = *per_cpu_ptr(zcache_comp_pcpu_tfms, get_cpu());
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BUG_ON(!tfm);
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switch (op) {
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case ZCACHE_COMPOP_COMPRESS:
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ret = crypto_comp_compress(tfm, src, slen, dst, dlen);
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break;
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case ZCACHE_COMPOP_DECOMPRESS:
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ret = crypto_comp_decompress(tfm, src, slen, dst, dlen);
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break;
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}
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put_cpu();
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return ret;
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}
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/**********
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* Compression buddies ("zbud") provides for packing two (or, possibly
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* in the future, more) compressed ephemeral pages into a single "raw"
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@ -408,7 +442,7 @@ static int zbud_decompress(struct page *page, struct zbud_hdr *zh)
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{
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struct zbud_page *zbpg;
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unsigned budnum = zbud_budnum(zh);
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size_t out_len = PAGE_SIZE;
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unsigned int out_len = PAGE_SIZE;
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char *to_va, *from_va;
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unsigned size;
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int ret = 0;
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@ -425,8 +459,9 @@ static int zbud_decompress(struct page *page, struct zbud_hdr *zh)
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to_va = kmap_atomic(page, KM_USER0);
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size = zh->size;
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from_va = zbud_data(zh, size);
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ret = lzo1x_decompress_safe(from_va, size, to_va, &out_len);
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BUG_ON(ret != LZO_E_OK);
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ret = zcache_comp_op(ZCACHE_COMPOP_DECOMPRESS, from_va, size,
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to_va, &out_len);
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BUG_ON(ret);
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BUG_ON(out_len != PAGE_SIZE);
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kunmap_atomic(to_va, KM_USER0);
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out:
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@ -624,7 +659,7 @@ static int zbud_show_cumul_chunk_counts(char *buf)
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/**********
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* This "zv" PAM implementation combines the TLSF-based xvMalloc
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* with lzo1x compression to maximize the amount of data that can
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* with the crypto compression API to maximize the amount of data that can
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* be packed into a physical page.
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*
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* Zv represents a PAM page with the index and object (plus a "size" value
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@ -711,7 +746,7 @@ static void zv_free(struct xv_pool *xvpool, struct zv_hdr *zv)
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static void zv_decompress(struct page *page, struct zv_hdr *zv)
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{
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size_t clen = PAGE_SIZE;
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unsigned int clen = PAGE_SIZE;
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char *to_va;
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unsigned size;
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int ret;
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@ -720,10 +755,10 @@ static void zv_decompress(struct page *page, struct zv_hdr *zv)
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size = xv_get_object_size(zv) - sizeof(*zv);
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BUG_ON(size == 0);
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to_va = kmap_atomic(page, KM_USER0);
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ret = lzo1x_decompress_safe((char *)zv + sizeof(*zv),
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size, to_va, &clen);
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ret = zcache_comp_op(ZCACHE_COMPOP_DECOMPRESS, (char *)zv + sizeof(*zv),
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size, to_va, &clen);
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kunmap_atomic(to_va, KM_USER0);
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BUG_ON(ret != LZO_E_OK);
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BUG_ON(ret);
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BUG_ON(clen != PAGE_SIZE);
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}
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@ -1286,25 +1321,24 @@ static struct tmem_pamops zcache_pamops = {
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* zcache compression/decompression and related per-cpu stuff
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*/
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#define LZO_WORKMEM_BYTES LZO1X_1_MEM_COMPRESS
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#define LZO_DSTMEM_PAGE_ORDER 1
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static DEFINE_PER_CPU(unsigned char *, zcache_workmem);
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static DEFINE_PER_CPU(unsigned char *, zcache_dstmem);
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#define ZCACHE_DSTMEM_ORDER 1
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static int zcache_compress(struct page *from, void **out_va, size_t *out_len)
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{
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int ret = 0;
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unsigned char *dmem = __get_cpu_var(zcache_dstmem);
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unsigned char *wmem = __get_cpu_var(zcache_workmem);
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char *from_va;
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BUG_ON(!irqs_disabled());
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if (unlikely(dmem == NULL || wmem == NULL))
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goto out; /* no buffer, so can't compress */
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if (unlikely(dmem == NULL))
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goto out; /* no buffer or no compressor so can't compress */
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*out_len = PAGE_SIZE << ZCACHE_DSTMEM_ORDER;
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from_va = kmap_atomic(from, KM_USER0);
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mb();
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ret = lzo1x_1_compress(from_va, PAGE_SIZE, dmem, out_len, wmem);
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BUG_ON(ret != LZO_E_OK);
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ret = zcache_comp_op(ZCACHE_COMPOP_COMPRESS, from_va, PAGE_SIZE, dmem,
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(unsigned int *)out_len);
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BUG_ON(ret);
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*out_va = dmem;
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kunmap_atomic(from_va, KM_USER0);
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ret = 1;
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@ -1312,29 +1346,48 @@ out:
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return ret;
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}
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static int zcache_comp_cpu_up(int cpu)
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{
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struct crypto_comp *tfm;
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tfm = crypto_alloc_comp(zcache_comp_name, 0, 0);
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if (IS_ERR(tfm))
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return NOTIFY_BAD;
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*per_cpu_ptr(zcache_comp_pcpu_tfms, cpu) = tfm;
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return NOTIFY_OK;
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}
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static void zcache_comp_cpu_down(int cpu)
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{
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struct crypto_comp *tfm;
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tfm = *per_cpu_ptr(zcache_comp_pcpu_tfms, cpu);
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crypto_free_comp(tfm);
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*per_cpu_ptr(zcache_comp_pcpu_tfms, cpu) = NULL;
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}
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static int zcache_cpu_notifier(struct notifier_block *nb,
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unsigned long action, void *pcpu)
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{
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int cpu = (long)pcpu;
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int ret, cpu = (long)pcpu;
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struct zcache_preload *kp;
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switch (action) {
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case CPU_UP_PREPARE:
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ret = zcache_comp_cpu_up(cpu);
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if (ret != NOTIFY_OK) {
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pr_err("zcache: can't allocate compressor transform\n");
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return ret;
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}
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per_cpu(zcache_dstmem, cpu) = (void *)__get_free_pages(
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GFP_KERNEL | __GFP_REPEAT,
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LZO_DSTMEM_PAGE_ORDER),
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per_cpu(zcache_workmem, cpu) =
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kzalloc(LZO1X_MEM_COMPRESS,
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GFP_KERNEL | __GFP_REPEAT);
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GFP_KERNEL | __GFP_REPEAT, ZCACHE_DSTMEM_ORDER);
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break;
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case CPU_DEAD:
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case CPU_UP_CANCELED:
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zcache_comp_cpu_down(cpu);
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free_pages((unsigned long)per_cpu(zcache_dstmem, cpu),
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LZO_DSTMEM_PAGE_ORDER);
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ZCACHE_DSTMEM_ORDER);
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per_cpu(zcache_dstmem, cpu) = NULL;
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kfree(per_cpu(zcache_workmem, cpu));
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per_cpu(zcache_workmem, cpu) = NULL;
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kp = &per_cpu(zcache_preloads, cpu);
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while (kp->nr) {
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kmem_cache_free(zcache_objnode_cache,
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__setup("nofrontswap", no_frontswap);
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static int __init enable_zcache_compressor(char *s)
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{
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strncpy(zcache_comp_name, s, ZCACHE_COMP_NAME_SZ);
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zcache_enabled = 1;
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return 1;
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}
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__setup("zcache=", enable_zcache_compressor);
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static int zcache_comp_init(void)
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{
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int ret = 0;
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/* check crypto algorithm */
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if (*zcache_comp_name != '\0') {
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ret = crypto_has_comp(zcache_comp_name, 0, 0);
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if (!ret)
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pr_info("zcache: %s not supported\n",
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zcache_comp_name);
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}
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if (!ret)
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strcpy(zcache_comp_name, "lzo");
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ret = crypto_has_comp(zcache_comp_name, 0, 0);
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if (!ret) {
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ret = 1;
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goto out;
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}
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pr_info("zcache: using %s compressor\n", zcache_comp_name);
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/* alloc percpu transforms */
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ret = 0;
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zcache_comp_pcpu_tfms = alloc_percpu(struct crypto_comp *);
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if (!zcache_comp_pcpu_tfms)
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ret = 1;
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out:
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return ret;
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}
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static int __init zcache_init(void)
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{
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int ret = 0;
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pr_err("zcache: can't register cpu notifier\n");
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goto out;
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}
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ret = zcache_comp_init();
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if (ret) {
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pr_err("zcache: compressor initialization failed\n");
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goto out;
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}
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for_each_online_cpu(cpu) {
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void *pcpu = (void *)(long)cpu;
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zcache_cpu_notifier(&zcache_cpu_notifier_block,
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