1b2441318SGreg Kroah-Hartman // SPDX-License-Identifier: GPL-2.0 28f933b10SRalf Hoppe /* 38f933b10SRalf Hoppe * SE/HMC Drive (Read) Cache Functions 48f933b10SRalf Hoppe * 58f933b10SRalf Hoppe * Copyright IBM Corp. 2013 68f933b10SRalf Hoppe * Author(s): Ralf Hoppe (rhoppe@de.ibm.com) 78f933b10SRalf Hoppe * 88f933b10SRalf Hoppe */ 98f933b10SRalf Hoppe 108f933b10SRalf Hoppe #define KMSG_COMPONENT "hmcdrv" 118f933b10SRalf Hoppe #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt 128f933b10SRalf Hoppe 138f933b10SRalf Hoppe #include <linux/kernel.h> 148f933b10SRalf Hoppe #include <linux/mm.h> 158f933b10SRalf Hoppe #include <linux/jiffies.h> 168f933b10SRalf Hoppe 178f933b10SRalf Hoppe #include "hmcdrv_ftp.h" 188f933b10SRalf Hoppe #include "hmcdrv_cache.h" 198f933b10SRalf Hoppe 208f933b10SRalf Hoppe #define HMCDRV_CACHE_TIMEOUT 30 /* aging timeout in seconds */ 218f933b10SRalf Hoppe 228f933b10SRalf Hoppe /** 238f933b10SRalf Hoppe * struct hmcdrv_cache_entry - file cache (only used on read/dir) 248f933b10SRalf Hoppe * @id: FTP command ID 258f933b10SRalf Hoppe * @content: kernel-space buffer, 4k aligned 268f933b10SRalf Hoppe * @len: size of @content cache (0 if caching disabled) 278f933b10SRalf Hoppe * @ofs: start of content within file (-1 if no cached content) 288f933b10SRalf Hoppe * @fname: file name 298f933b10SRalf Hoppe * @fsize: file size 308f933b10SRalf Hoppe * @timeout: cache timeout in jiffies 318f933b10SRalf Hoppe * 328f933b10SRalf Hoppe * Notice that the first three members (id, fname, fsize) are cached on all 338f933b10SRalf Hoppe * read/dir requests. But content is cached only under some preconditions. 348f933b10SRalf Hoppe * Uncached content is signalled by a negative value of @ofs. 358f933b10SRalf Hoppe */ 368f933b10SRalf Hoppe struct hmcdrv_cache_entry { 378f933b10SRalf Hoppe enum hmcdrv_ftp_cmdid id; 388f933b10SRalf Hoppe char fname[HMCDRV_FTP_FIDENT_MAX]; 398f933b10SRalf Hoppe size_t fsize; 408f933b10SRalf Hoppe loff_t ofs; 418f933b10SRalf Hoppe unsigned long timeout; 428f933b10SRalf Hoppe void *content; 438f933b10SRalf Hoppe size_t len; 448f933b10SRalf Hoppe }; 458f933b10SRalf Hoppe 468f933b10SRalf Hoppe static int hmcdrv_cache_order; /* cache allocated page order */ 478f933b10SRalf Hoppe 488f933b10SRalf Hoppe static struct hmcdrv_cache_entry hmcdrv_cache_file = { 498f933b10SRalf Hoppe .fsize = SIZE_MAX, 508f933b10SRalf Hoppe .ofs = -1, 518f933b10SRalf Hoppe .len = 0, 528f933b10SRalf Hoppe .fname = {'\0'} 538f933b10SRalf Hoppe }; 548f933b10SRalf Hoppe 558f933b10SRalf Hoppe /** 568f933b10SRalf Hoppe * hmcdrv_cache_get() - looks for file data/content in read cache 578f933b10SRalf Hoppe * @ftp: pointer to FTP command specification 588f933b10SRalf Hoppe * 598f933b10SRalf Hoppe * Return: number of bytes read from cache or a negative number if nothing 608f933b10SRalf Hoppe * in content cache (for the file/cmd specified in @ftp) 618f933b10SRalf Hoppe */ 628f933b10SRalf Hoppe static ssize_t hmcdrv_cache_get(const struct hmcdrv_ftp_cmdspec *ftp) 638f933b10SRalf Hoppe { 648f933b10SRalf Hoppe loff_t pos; /* position in cache (signed) */ 658f933b10SRalf Hoppe ssize_t len; 668f933b10SRalf Hoppe 678f933b10SRalf Hoppe if ((ftp->id != hmcdrv_cache_file.id) || 688f933b10SRalf Hoppe strcmp(hmcdrv_cache_file.fname, ftp->fname)) 698f933b10SRalf Hoppe return -1; 708f933b10SRalf Hoppe 718f933b10SRalf Hoppe if (ftp->ofs >= hmcdrv_cache_file.fsize) /* EOF ? */ 728f933b10SRalf Hoppe return 0; 738f933b10SRalf Hoppe 748f933b10SRalf Hoppe if ((hmcdrv_cache_file.ofs < 0) || /* has content? */ 758f933b10SRalf Hoppe time_after(jiffies, hmcdrv_cache_file.timeout)) 768f933b10SRalf Hoppe return -1; 778f933b10SRalf Hoppe 788f933b10SRalf Hoppe /* there seems to be cached content - calculate the maximum number 798f933b10SRalf Hoppe * of bytes that can be returned (regarding file size and offset) 808f933b10SRalf Hoppe */ 818f933b10SRalf Hoppe len = hmcdrv_cache_file.fsize - ftp->ofs; 828f933b10SRalf Hoppe 838f933b10SRalf Hoppe if (len > ftp->len) 848f933b10SRalf Hoppe len = ftp->len; 858f933b10SRalf Hoppe 868f933b10SRalf Hoppe /* check if the requested chunk falls into our cache (which starts 878f933b10SRalf Hoppe * at offset 'hmcdrv_cache_file.ofs' in the file of interest) 888f933b10SRalf Hoppe */ 898f933b10SRalf Hoppe pos = ftp->ofs - hmcdrv_cache_file.ofs; 908f933b10SRalf Hoppe 918f933b10SRalf Hoppe if ((pos >= 0) && 928f933b10SRalf Hoppe ((pos + len) <= hmcdrv_cache_file.len)) { 938f933b10SRalf Hoppe 948f933b10SRalf Hoppe memcpy(ftp->buf, 958f933b10SRalf Hoppe hmcdrv_cache_file.content + pos, 968f933b10SRalf Hoppe len); 978f933b10SRalf Hoppe pr_debug("using cached content of '%s', returning %zd/%zd bytes\n", 988f933b10SRalf Hoppe hmcdrv_cache_file.fname, len, 998f933b10SRalf Hoppe hmcdrv_cache_file.fsize); 1008f933b10SRalf Hoppe 1018f933b10SRalf Hoppe return len; 1028f933b10SRalf Hoppe } 1038f933b10SRalf Hoppe 1048f933b10SRalf Hoppe return -1; 1058f933b10SRalf Hoppe } 1068f933b10SRalf Hoppe 1078f933b10SRalf Hoppe /** 1088f933b10SRalf Hoppe * hmcdrv_cache_do() - do a HMC drive CD/DVD transfer with cache update 1098f933b10SRalf Hoppe * @ftp: pointer to FTP command specification 1108f933b10SRalf Hoppe * @func: FTP transfer function to be used 1118f933b10SRalf Hoppe * 1128f933b10SRalf Hoppe * Return: number of bytes read/written or a (negative) error code 1138f933b10SRalf Hoppe */ 1148f933b10SRalf Hoppe static ssize_t hmcdrv_cache_do(const struct hmcdrv_ftp_cmdspec *ftp, 1158f933b10SRalf Hoppe hmcdrv_cache_ftpfunc func) 1168f933b10SRalf Hoppe { 1178f933b10SRalf Hoppe ssize_t len; 1188f933b10SRalf Hoppe 1198f933b10SRalf Hoppe /* only cache content if the read/dir cache really exists 1208f933b10SRalf Hoppe * (hmcdrv_cache_file.len > 0), is large enough to handle the 1218f933b10SRalf Hoppe * request (hmcdrv_cache_file.len >= ftp->len) and there is a need 1228f933b10SRalf Hoppe * to do so (ftp->len > 0) 1238f933b10SRalf Hoppe */ 1248f933b10SRalf Hoppe if ((ftp->len > 0) && (hmcdrv_cache_file.len >= ftp->len)) { 1258f933b10SRalf Hoppe 1268f933b10SRalf Hoppe /* because the cache is not located at ftp->buf, we have to 1278f933b10SRalf Hoppe * assemble a new HMC drive FTP cmd specification (pointing 1288f933b10SRalf Hoppe * to our cache, and using the increased size) 1298f933b10SRalf Hoppe */ 1308f933b10SRalf Hoppe struct hmcdrv_ftp_cmdspec cftp = *ftp; /* make a copy */ 1318f933b10SRalf Hoppe cftp.buf = hmcdrv_cache_file.content; /* and update */ 1328f933b10SRalf Hoppe cftp.len = hmcdrv_cache_file.len; /* buffer data */ 1338f933b10SRalf Hoppe 1348f933b10SRalf Hoppe len = func(&cftp, &hmcdrv_cache_file.fsize); /* now do */ 1358f933b10SRalf Hoppe 1368f933b10SRalf Hoppe if (len > 0) { 1378f933b10SRalf Hoppe pr_debug("caching %zd bytes content for '%s'\n", 1388f933b10SRalf Hoppe len, ftp->fname); 1398f933b10SRalf Hoppe 1408f933b10SRalf Hoppe if (len > ftp->len) 1418f933b10SRalf Hoppe len = ftp->len; 1428f933b10SRalf Hoppe 1438f933b10SRalf Hoppe hmcdrv_cache_file.ofs = ftp->ofs; 1448f933b10SRalf Hoppe hmcdrv_cache_file.timeout = jiffies + 1458f933b10SRalf Hoppe HMCDRV_CACHE_TIMEOUT * HZ; 1468f933b10SRalf Hoppe memcpy(ftp->buf, hmcdrv_cache_file.content, len); 1478f933b10SRalf Hoppe } 1488f933b10SRalf Hoppe } else { 1498f933b10SRalf Hoppe len = func(ftp, &hmcdrv_cache_file.fsize); 1508f933b10SRalf Hoppe hmcdrv_cache_file.ofs = -1; /* invalidate content */ 1518f933b10SRalf Hoppe } 1528f933b10SRalf Hoppe 1538f933b10SRalf Hoppe if (len > 0) { 1548f933b10SRalf Hoppe /* cache some file info (FTP command, file name and file 1558f933b10SRalf Hoppe * size) unconditionally 1568f933b10SRalf Hoppe */ 157*820109fbSWolfram Sang strscpy(hmcdrv_cache_file.fname, ftp->fname, 1588f933b10SRalf Hoppe HMCDRV_FTP_FIDENT_MAX); 1598f933b10SRalf Hoppe hmcdrv_cache_file.id = ftp->id; 1608f933b10SRalf Hoppe pr_debug("caching cmd %d, file size %zu for '%s'\n", 1618f933b10SRalf Hoppe ftp->id, hmcdrv_cache_file.fsize, ftp->fname); 1628f933b10SRalf Hoppe } 1638f933b10SRalf Hoppe 1648f933b10SRalf Hoppe return len; 1658f933b10SRalf Hoppe } 1668f933b10SRalf Hoppe 1678f933b10SRalf Hoppe /** 1688f933b10SRalf Hoppe * hmcdrv_cache_cmd() - perform a cached HMC drive CD/DVD transfer 1698f933b10SRalf Hoppe * @ftp: pointer to FTP command specification 1708f933b10SRalf Hoppe * @func: FTP transfer function to be used 1718f933b10SRalf Hoppe * 1728f933b10SRalf Hoppe * Attention: Notice that this function is not reentrant - so the caller 1738f933b10SRalf Hoppe * must ensure exclusive execution. 1748f933b10SRalf Hoppe * 1758f933b10SRalf Hoppe * Return: number of bytes read/written or a (negative) error code 1768f933b10SRalf Hoppe */ 1778f933b10SRalf Hoppe ssize_t hmcdrv_cache_cmd(const struct hmcdrv_ftp_cmdspec *ftp, 1788f933b10SRalf Hoppe hmcdrv_cache_ftpfunc func) 1798f933b10SRalf Hoppe { 1808f933b10SRalf Hoppe ssize_t len; 1818f933b10SRalf Hoppe 1828f933b10SRalf Hoppe if ((ftp->id == HMCDRV_FTP_DIR) || /* read cache */ 1838f933b10SRalf Hoppe (ftp->id == HMCDRV_FTP_NLIST) || 1848f933b10SRalf Hoppe (ftp->id == HMCDRV_FTP_GET)) { 1858f933b10SRalf Hoppe 1868f933b10SRalf Hoppe len = hmcdrv_cache_get(ftp); 1878f933b10SRalf Hoppe 1888f933b10SRalf Hoppe if (len >= 0) /* got it from cache ? */ 1898f933b10SRalf Hoppe return len; /* yes */ 1908f933b10SRalf Hoppe 1918f933b10SRalf Hoppe len = hmcdrv_cache_do(ftp, func); 1928f933b10SRalf Hoppe 1938f933b10SRalf Hoppe if (len >= 0) 1948f933b10SRalf Hoppe return len; 1958f933b10SRalf Hoppe 1968f933b10SRalf Hoppe } else { 1978f933b10SRalf Hoppe len = func(ftp, NULL); /* simply do original command */ 1988f933b10SRalf Hoppe } 1998f933b10SRalf Hoppe 2008f933b10SRalf Hoppe /* invalidate the (read) cache in case there was a write operation 2018f933b10SRalf Hoppe * or an error on read/dir 2028f933b10SRalf Hoppe */ 2038f933b10SRalf Hoppe hmcdrv_cache_file.id = HMCDRV_FTP_NOOP; 2048f933b10SRalf Hoppe hmcdrv_cache_file.fsize = LLONG_MAX; 2058f933b10SRalf Hoppe hmcdrv_cache_file.ofs = -1; 2068f933b10SRalf Hoppe 2078f933b10SRalf Hoppe return len; 2088f933b10SRalf Hoppe } 2098f933b10SRalf Hoppe 2108f933b10SRalf Hoppe /** 2118f933b10SRalf Hoppe * hmcdrv_cache_startup() - startup of HMC drive cache 2128f933b10SRalf Hoppe * @cachesize: cache size 2138f933b10SRalf Hoppe * 2148f933b10SRalf Hoppe * Return: 0 on success, else a (negative) error code 2158f933b10SRalf Hoppe */ 2168f933b10SRalf Hoppe int hmcdrv_cache_startup(size_t cachesize) 2178f933b10SRalf Hoppe { 2188f933b10SRalf Hoppe if (cachesize > 0) { /* perform caching ? */ 2198f933b10SRalf Hoppe hmcdrv_cache_order = get_order(cachesize); 2208f933b10SRalf Hoppe hmcdrv_cache_file.content = 2218f933b10SRalf Hoppe (void *) __get_free_pages(GFP_KERNEL | GFP_DMA, 2228f933b10SRalf Hoppe hmcdrv_cache_order); 2238f933b10SRalf Hoppe 2248f933b10SRalf Hoppe if (!hmcdrv_cache_file.content) { 2258f933b10SRalf Hoppe pr_err("Allocating the requested cache size of %zu bytes failed\n", 2268f933b10SRalf Hoppe cachesize); 2278f933b10SRalf Hoppe return -ENOMEM; 2288f933b10SRalf Hoppe } 2298f933b10SRalf Hoppe 2308f933b10SRalf Hoppe pr_debug("content cache enabled, size is %zu bytes\n", 2318f933b10SRalf Hoppe cachesize); 2328f933b10SRalf Hoppe } 2338f933b10SRalf Hoppe 2348f933b10SRalf Hoppe hmcdrv_cache_file.len = cachesize; 2358f933b10SRalf Hoppe return 0; 2368f933b10SRalf Hoppe } 2378f933b10SRalf Hoppe 2388f933b10SRalf Hoppe /** 2398f933b10SRalf Hoppe * hmcdrv_cache_shutdown() - shutdown of HMC drive cache 2408f933b10SRalf Hoppe */ 2418f933b10SRalf Hoppe void hmcdrv_cache_shutdown(void) 2428f933b10SRalf Hoppe { 2438f933b10SRalf Hoppe if (hmcdrv_cache_file.content) { 2448f933b10SRalf Hoppe free_pages((unsigned long) hmcdrv_cache_file.content, 2458f933b10SRalf Hoppe hmcdrv_cache_order); 2468f933b10SRalf Hoppe hmcdrv_cache_file.content = NULL; 2478f933b10SRalf Hoppe } 2488f933b10SRalf Hoppe 2498f933b10SRalf Hoppe hmcdrv_cache_file.id = HMCDRV_FTP_NOOP; 2508f933b10SRalf Hoppe hmcdrv_cache_file.fsize = LLONG_MAX; 2518f933b10SRalf Hoppe hmcdrv_cache_file.ofs = -1; 2528f933b10SRalf Hoppe hmcdrv_cache_file.len = 0; /* no cache */ 2538f933b10SRalf Hoppe } 254