04 task struct #126
04 task struct #126
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marynamalakhova
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04_basic_struct/Makefile
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| @@ -0,0 +1,7 @@ | |||
| TARGET = bstructmodule | |||
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The task says Implement object with name “hello”
04_basic_struct/Makefile
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| @@ -0,0 +1,7 @@ | |||
| TARGET = bstructmodule | |||
| obj-m+=$(TARGET).o | |||
04_basic_struct/bstructmodule.c
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| #include <linux/init.h> // Macros used to mark up functions __init __exit | ||
| #include <linux/module.h> // Core header for loading LKMs into the kernel |
04_basic_struct/bstructmodule.c
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| sscanf(buf, "%d\n", &value); | ||
| pr_info("hello_store: value = %d\n", value); | ||
| return count; |
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please add error handling
04_basic_struct/bstructmodule.c
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| if (!hello_kobj) | ||
| return -ENOMEM; | ||
| /* Create the files associated with this kobject */ | ||
| res = sysfs_create_group(hello_kobj, &attr_group); |
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What's the purpose of using group API for a single attribute?
04_basic_struct/bstructmodule.c
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| struct list_head head_list; | ||
| }; | ||
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| LIST_HEAD(linkedlist); |
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It's usually bad idea to define global variables with such generic name.
Please limit its scope.
04_basic_struct/bstructmodule.c
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| if (new_node->node == NULL) | ||
| return -ENOMEM; | ||
| list_add_tail(&new_node->head_list, &linkedlist); | ||
| pr_info("store nodes: Added node = %s", buf); |
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It's not a big deal, but prefer referencing actually added node instead of user buffer.
Also please don't forget newline explicit character for complete messages. (in other places as well)
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kstrdup allocates space for and copy an existing string. That's why nodes have been already stored with the end of the string. When we are printing out the nodes extra newline explicit character seems redundant
04_basic_struct/bstructmodule.c
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| list_for_each_entry(cur_node, &linkedlist, head_list) { | ||
| res = scnprintf(buf+offset, PAGE_SIZE-offset, "%s", cur_node->node); | ||
| offset += res; | ||
| } |
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IMO it makes sense to somehow separate entries in the output.
| /mnt # | ||
| /mnt # lsmod | ||
| /mnt # | ||
|
|
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Please don't mix implementation and test logs in the same commit.
AleksandrBulyshchenko
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Change requested
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Added simple module that provides basic operations with /sys/kernel/hello/list Variable BUILD_KERNEL should be set in the environment for building BUILD_KERNEL should define path to the linux kernel source folder Signed-off-by: Maryna Malakhova <[email protected]>
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Add list of strings insted of int value Signed-off-by: Maryna Malakhova <[email protected]>
Add BBB log Signed-off-by: Maryna Malakhova <[email protected]>
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marynamalakhova
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Ready for review
|
Thank you for the review, I've fixed |
Module has been created that could store parameters list in /sys/kernel/hello/list