block/partitions/amiga.c

Source file repositories/reference/linux-study-clean/block/partitions/amiga.c

File Facts

System
Linux kernel
Corpus path
block/partitions/amiga.c
Extension
.c
Size
5742 bytes
Lines
202
Domain
Representative Device Path
Bucket
PCIe NVMe Storage Path
Inferred role
Representative Device Path: implementation source
Status
source implementation candidate

Why This File Exists

Part of the selected hardware vertical slice: PCI discovery, driver binding, NVMe queues, block requests, DMA, interrupts, and completion.

Dependency Surface

Detected Declarations

Annotated Snippet

if (!data) {
			pr_err("Dev %s: unable to read RDB block %llu\n",
			       state->disk->disk_name, blk);
			res = -1;
			goto rdb_done;
		}
		if (*(__be32 *)data != cpu_to_be32(IDNAME_RIGIDDISK))
			continue;

		rdb = (struct RigidDiskBlock *)data;
		if (checksum_block((__be32 *)data, be32_to_cpu(rdb->rdb_SummedLongs) & 0x7F) == 0)
			break;
		/* Try again with 0xdc..0xdf zeroed, Windows might have
		 * trashed it.
		 */
		*(__be32 *)(data+0xdc) = 0;
		if (checksum_block((__be32 *)data,
				be32_to_cpu(rdb->rdb_SummedLongs) & 0x7F)==0) {
			pr_err("Trashed word at 0xd0 in block %llu ignored in checksum calculation\n",
			       blk);
			break;
		}

		pr_err("Dev %s: RDB in block %llu has bad checksum\n",
		       state->disk->disk_name, blk);
	}

	/* blksize is blocks per 512 byte standard block */
	blksize = be32_to_cpu( rdb->rdb_BlockBytes ) / 512;

	/* Be more informative */
	seq_buf_printf(&state->pp_buf, " RDSK (%d)", blksize * 512);
	blk = be32_to_cpu(rdb->rdb_PartitionList);
	put_dev_sector(sect);
	for (part = 1; (s32) blk>0 && part<=16; part++, put_dev_sector(sect)) {
		/* Read in terms partition table understands */
		if (check_mul_overflow(blk, (sector_t) blksize, &blk)) {
			pr_err("Dev %s: overflow calculating partition block %llu! Skipping partitions %u and beyond\n",
				state->disk->disk_name, blk, part);
			break;
		}
		data = read_part_sector(state, blk, &sect);
		if (!data) {
			pr_err("Dev %s: unable to read partition block %llu\n",
			       state->disk->disk_name, blk);
			res = -1;
			goto rdb_done;
		}
		pb  = (struct PartitionBlock *)data;
		blk = be32_to_cpu(pb->pb_Next);
		if (pb->pb_ID != cpu_to_be32(IDNAME_PARTITION))
			continue;
		if (checksum_block((__be32 *)pb, be32_to_cpu(pb->pb_SummedLongs) & 0x7F) != 0 )
			continue;

		/* RDB gives us more than enough rope to hang ourselves with,
		 * many times over (2^128 bytes if all fields max out).
		 * Some careful checks are in order, so check for potential
		 * overflows.
		 * We are multiplying four 32 bit numbers to one sector_t!
		 */

		nr_hd   = be32_to_cpu(pb->pb_Environment[NR_HD]);
		nr_sect = be32_to_cpu(pb->pb_Environment[NR_SECT]);

		/* CylBlocks is total number of blocks per cylinder */
		if (check_mul_overflow(nr_hd, nr_sect, &cylblk)) {
			pr_err("Dev %s: heads*sects %u overflows u32, skipping partition!\n",
				state->disk->disk_name, cylblk);
			continue;
		}

		/* check for consistency with RDB defined CylBlocks */
		if (cylblk > be32_to_cpu(rdb->rdb_CylBlocks)) {
			pr_warn("Dev %s: cylblk %u > rdb_CylBlocks %u!\n",
				state->disk->disk_name, cylblk,
				be32_to_cpu(rdb->rdb_CylBlocks));
		}

		/* RDB allows for variable logical block size -
		 * normalize to 512 byte blocks and check result.
		 */

		if (check_mul_overflow(cylblk, blksize, &cylblk)) {
			pr_err("Dev %s: partition %u bytes per cyl. overflows u32, skipping partition!\n",
				state->disk->disk_name, part);
			continue;
		}

		/* Calculate partition start and end. Limit of 32 bit on cylblk

Annotation

Implementation Notes