1 // SPDX-License-Identifier: GPL-2.0
3  *    SE/HMC Drive (Read) Cache Functions
23  * struct hmcdrv_cache_entry - file cache (only used on read/dir)
25  * @content: kernel-space buffer, 4k aligned
27  * @ofs: start of content within file (-1 if no cached content)
50 	.ofs = -1,
56  * hmcdrv_cache_get() - looks for file data/content in read cache
64 	loff_t pos; /* position in cache (signed) */  in hmcdrv_cache_get()  local
67 	if ((ftp->id != hmcdrv_cache_file.id) ||  in hmcdrv_cache_get()
68 	    strcmp(hmcdrv_cache_file.fname, ftp->fname))  in hmcdrv_cache_get()
69 		return -1;  in hmcdrv_cache_get()
71 	if (ftp->ofs >= hmcdrv_cache_file.fsize) /* EOF ? */  in hmcdrv_cache_get()
76 		return -1;  in hmcdrv_cache_get()
78 	/* there seems to be cached content - calculate the maximum number  in hmcdrv_cache_get()
81 	len = hmcdrv_cache_file.fsize - ftp->ofs;  in hmcdrv_cache_get()
83 	if (len > ftp->len)  in hmcdrv_cache_get()
84 		len = ftp->len;  in hmcdrv_cache_get()
89 	pos = ftp->ofs - hmcdrv_cache_file.ofs;  in hmcdrv_cache_get()
91 	if ((pos >= 0) &&  in hmcdrv_cache_get()
92 	    ((pos + len) <= hmcdrv_cache_file.len)) {  in hmcdrv_cache_get()
94 		memcpy(ftp->buf,  in hmcdrv_cache_get()
95 		       hmcdrv_cache_file.content + pos,  in hmcdrv_cache_get()
104 	return -1;  in hmcdrv_cache_get()
108  * hmcdrv_cache_do() - do a HMC drive CD/DVD transfer with cache update
121 	 * request (hmcdrv_cache_file.len >= ftp->len) and there is a need  in hmcdrv_cache_do()
122 	 * to do so (ftp->len > 0)  in hmcdrv_cache_do()
124 	if ((ftp->len > 0) && (hmcdrv_cache_file.len >= ftp->len)) {  in hmcdrv_cache_do()
126 		/* because the cache is not located at ftp->buf, we have to  in hmcdrv_cache_do()
138 				 len, ftp->fname);  in hmcdrv_cache_do()
140 			if (len > ftp->len)  in hmcdrv_cache_do()
141 				len = ftp->len;  in hmcdrv_cache_do()
143 			hmcdrv_cache_file.ofs = ftp->ofs;  in hmcdrv_cache_do()
146 			memcpy(ftp->buf, hmcdrv_cache_file.content, len);  in hmcdrv_cache_do()
150 		hmcdrv_cache_file.ofs = -1; /* invalidate content */  in hmcdrv_cache_do()
157 		strscpy(hmcdrv_cache_file.fname, ftp->fname,  in hmcdrv_cache_do()
159 		hmcdrv_cache_file.id = ftp->id;  in hmcdrv_cache_do()
161 			 ftp->id, hmcdrv_cache_file.fsize, ftp->fname);  in hmcdrv_cache_do()
168  * hmcdrv_cache_cmd() - perform a cached HMC drive CD/DVD transfer
172  * Attention: Notice that this function is not reentrant - so the caller
182 	if ((ftp->id == HMCDRV_FTP_DIR) || /* read cache */  in hmcdrv_cache_cmd()
183 	    (ftp->id == HMCDRV_FTP_NLIST) ||  in hmcdrv_cache_cmd()
184 	    (ftp->id == HMCDRV_FTP_GET)) {  in hmcdrv_cache_cmd()
205 	hmcdrv_cache_file.ofs = -1;  in hmcdrv_cache_cmd()
211  * hmcdrv_cache_startup() - startup of HMC drive cache
227 			return -ENOMEM;  in hmcdrv_cache_startup()
239  * hmcdrv_cache_shutdown() - shutdown of HMC drive cache
251 	hmcdrv_cache_file.ofs = -1;  in hmcdrv_cache_shutdown()